Java Interview Questions - Part3

Q 1. What is the output of the following

StringBuffer sb1 = new StringBuffer("Amit");
StringBuffer sb2= new StringBuffer("Amit");
String ss1 = "Amit";
System.out.println(sb1==sb2);
System.out.println(sb1.equals(sb2));
System.out.println(sb1.equals(ss1));
System.out.println("Poddar".substring(3));
Ans:
a) false
false
false
dar
b) false
true
false
Poddar
c) Compiler Error
d) true
true
false
dar
Correct Answer is a)
***** Look carefully at code and answer the following questions ( Q2 to Q8)
1 import java.applet.Applet;
2 import java.awt.*;
3 import java.awt.event.*;
4 public class hello4 extends Applet {
5 public void init(){
6 add(new myButton("BBB"));
7 }
8 public void paint(Graphics screen) {
9 }
10 class myButton extends Button{
11 myButton(String label){
12 super(label);
13 }
14 public String paramString(){
15 return super.paramString();
16 }
17 }
18 public static void main(String[] args){
19 Frame myFrame = new Frame(
20 "Copyright Amit");
21 myFrame.setSize(300,100);
22 Applet myApplet = new hello4();
23 Button b = new Button("My Button");
24 myApplet.add(b);
25 b.setLabel(b.getLabel()+"New");
26 // myButton b1 =(new hello4()).new myButton("PARAMBUTTON");
27 System.out.println(b1.paramString());
28 myFrame.add(myApplet);
29 myFrame.setVisible(true);
30 myFrame.addWindowListener(new WindowAdapter(){
31 public void windowClosing(WindowEvent e){
32 System.exit(0);}});
33 }
34 } //End hello4 class.

Q2. If you run the above program via appletviewer ( defining a HTML file), You see on screen.
a) Two buttons
b) One button with label as "BBB"
c) One button with label as "My ButtonNew"
d) One button with label as "My Button"
Correct answer is b)

Q3. In the above code if line 26 is uncommented and program runs as standalone application
a) Compile Error
b) Run time error
c) It will print the the label as PARAMBUTTON for button b1
Correct answer is c)

Q4 In the code if you compile as "javac hello4.java" following files will be generated.
a) hello4.class, myButton.class,hello41.class
b)hello4.class, hello4$myButton.class,hello4$1.class
c)hello4.clas,hello4$myButton.class
Correct answer is b)

Q5. If above program is run as a standalone application. How many buttons will be displayed
a) Two buttons
b) One button with label as "BBB"
c) One button with label as "My ButtonNew"
d) One button with label as "My Button"
correct answer is C)

Q6. If from line no 14 keyword "public" is removed, what will happen.( Hint :paramString() method in java.awt.Button is a protected method. (Assume line 26 is uncommented)
a) Code will not compile.
b) Code will compile but will give a run time error.
c) Code will compile and no run time error.
Correct answer is a). As you can not override a method with weaker access privileges

Q7. If from line no 14 keyword "public" is replaced with "protected", what will happen.(Hint :paramString() method in java.awt.Button is a protected method.(Assume line 26 is uncommented)
a) Code will not compile.
b) Code will compile but will give a run time error.
c) Code will compile and no run time error.
Correct answer is c) . As you can access a protected variable in the same package.

Q8.If line no 26 is replaced with Button b1 = new Button("PARAMBUTTON").(Hint :paramString() method in java.awt.Button is a protected method.(Assume line 26 is uncommented)
a) Code will not compile.
b) Code will compile but will give a run time error.
c) Code will compile and no run time error.
Correct answer is a) Because protected variables and methods can not be accssed in another package directly. They can only be accessed if the class is subclassed and instance of subclass is used.

Q9. What is the output of following if the return value is "the value 0 if the argument string is equal to this string; a value less than 0 if this string is lexicographically less than the string argument; and a value greater than 0 if this string is lexicographically greater than the string argument" (Assuming written inside main)
String s5 = "AMIT";
String s6 = "amit";
System.out.println(s5.compareTo(s6));
System.out.println(s6.compareTo(s5));
System.out.println(s6.compareTo(s6));
Ans
a> -32
32
0
b> 32
32
0
c> 32
-32
0
d> 0
0
0
Correct Answer is a)

Q10) What is the output (Assuming written inside main)
String s1 = new String("amit");
String s2 = s1.replace('m','i');
s1.concat("Poddar");
System.out.println(s1);
System.out.println((s1+s2).charAt(5));
a) Compile error
b) amitPoddar
o
c) amitPoddar
i
d) amit
i
Correct answer is d)As String is imutable.so s1 is always "amit". and s2 is "aiit".

Q11) What is the output (Assuming written inside main)
String s1 = new String("amit");
System.out.println(s1.replace('m','r'));
System.out.println(s1);
String s3="arit";
String s4="arit";
String s2 = s1.replace('m','r');
System.out.println(s2==s3);
System.out.println(s3==s4);
a) arit
amit
false
true
b) arit
arit
false
true
c) amit
amit
false
true
d) arit
amit
true
true
Correct answer is a) s3==s4 is true because java points both s3 and s4 to same memory location in string pool

Q12) Which one does not extend java.lang.Number
1)Integer
2)Boolean
3)Character
4)Long
5)Short
Correct answer is 2) and 3)

Q13) Which one does not have a valueOf(String) method
1)Integer
2)Boolean
3)Character
4)Long
5)Short
Correct answer is 3)

Q.14) What is the output of following (Assuming written inside main)
String s1 = "Amit";
String s2 = "Amit";
String s3 = new String("abcd");
String s4 = new String("abcd");
System.out.println(s1.equals(s2));
System.out.println((s1==s2));
System.out.println(s3.equals(s4));
System.out.println((s3==s4));
a) true
true
true
false
b) true
true
true
true
c) true
false
true
false
Correct answer is a)

Q15. Which checkbox will be selected in the following code ( Assume with main and added to a Frame)
Frame myFrame = new Frame("Test");
CheckboxGroup cbg = new CheckboxGroup();
Checkbox cb1 = new Checkbox("First",true,cbg);
Checkbox cb2 = new Checkbox("Scond",true,cbg);
Checkbox cb3 = new Checkbox("THird",false,cbg);
cbg.setSelectedCheckbox(cb3);
myFrame.add(cb1);
myFrame.add(cb2);
myFrame.add(cb3);
a) cb1
b) cb2,cb1
c) cb1,cb2,cb3
d) cb3
Correct Answer is d) As in a CheckboxGroup only one can be selected

Q16) Which checkbox will be selected in the following code ( Assume with main and added to a Frame)
Frame myFrame = new Frame("Test");
CheckboxGroup cbg = new CheckboxGroup();
Checkbox cb1 = new Checkbox("First",true,cbg);
Checkbox cb2 = new Checkbox("Scond",true,cbg);
Checkbox cb3 = new Checkbox("THird",true,cbg);
myFrame.add(cb1);
myFrame.add(cb2);
myFrame.add(cb3);
a) cb1
b) cb2,cb1
c) cb1,cb2,cb3
d) cb3
Correct Answer is d) As in a CheckboxGroup only one can be selected

Q17) What will be the output of line 5
1 Choice c1 = new Choice();
2 c1.add("First");
3 c1.addItem("Second");
4 c1.add("Third");
5 System.out.println(c1.getItemCount());
a) 1
b) 2
c) 3
d) None of the above
Correct Answer is c)
Q18) What will be the order of four items added
Choice c1 = new Choice();
c1.add("First");
c1.addItem("Second");
c1.add("Third");
c1.insert("Lastadded",2);
System.out.println(c1.getItemCount());
a) First,Second,Third,Fourth
b) First,Second,Lastadded,Third
c) Lastadded,First,Second,Third
Correct ANswer is b)

Q19) Answer based on following code
1 Choice c1 = new Choice();
2 c1.add("First");
3 c1.addItem("Second");
4 c1.add("Third");
5 c1.insert("Lastadded",1000);
6 System.out.println(c1.getItemCount());
a) Compile time error
b) Run time error at line 5
c) No error and line 6 will print 1000
d) No error and line 6 will print 4
Correct ANswer is d)

Q20) Which one of the following does not extends java.awt.Component
a) CheckBox
b) Canvas
c) CheckbocGroup
d) Label
Correct answer is c)

Q21) What is default layout manager for panels and applets?
a) Flowlayout
b) Gridlayout
c) BorderLayout
Correct answer is a)

Q22) For awt components which of the following statements are true?
a) If a component is not explicitly assigned a font, it usese the same font that it container uses.
b) If a component is not explicitly assigned a foreground color , it usese the same foreground color that it container uses.
c) If a component is not explicitly assigned a backround color , it usese the same background color that it container uses.
d) If a component is not explicitly assigned a layout manager , it usese the same layout manager that it container uses.
correct answer is a),b),c)

Q23)java.awt.Component class method getLocation() returns Point (containg x and y cordinate).What does this x and y specify
a) Specify the postion of components lower-left component in the coordinate space of the component's parent.
b) Specify the postion of components upper-left component in the coordinate space of the component's parent.
c) Specify the postion of components upper-left component in the coordinate space of the screen.
correct answer is b)

Q24. What will be the output of follwing
{
double d1 = -0.5d;
System.out.println("Ceil for d1 " + Math.ceil(d1));
System.out.println("Floor for d1 " +Math.floor(d1));
}
Answers:
a) Ceil for d1 0
Floor for d1 -1;
b) Ceil for d1 0
Floor for d1 -1.0;
c) Ceil for d1 0.0
Floor for d1 -1.0;
d) Ceil for d1 -0.0
Floor for d1 -1.0;
correct answer is d) as 0.0 is treated differently from -0.0

Q25. What is the output of following
{
float f4 = -5.5f;
float f5 = 5.5f;
float f6 = -5.49f;
float f7 = 5.49f;
System.out.println("Round f4 is " + Math.round(f4));
System.out.println("Round f5 is " + Math.round(f5));
System.out.println("Round f6 is " + Math.round(f6));
System.out.println("Round f7 is " + Math.round(f7));
}
a)Round f4 is -6
Round f5 is 6
Round f6 is -5
Round f7 is 5
b)Round f4 is -5
Round f5 is 6
Round f6 is -5
Round f7 is 5
Correct answer is b)

Q26. Given Integer.MIN_VALUE = -2147483648
Integer.MAX_VALUE = 2147483647
What is the output of following
{
float f4 = Integer.MIN_VALUE;
float f5 = Integer.MAX_VALUE;
float f7 = -2147483655f;
System.out.println("Round f4 is " + Math.round(f4));
System.out.println("Round f5 is " + Math.round(f5));
System.out.println("Round f7 is " + Math.round(f7));
}
a)Round f4 is -2147483648
Round f5 is 2147483647
Round f7 is -2147483648
b)Round f4 is -2147483648
Round f5 is 2147483647
Round f7 is -2147483655
correct answer is a)
//Reason If the argument is negative infinity or any value less than or equal to the value of Integer.MIN_VALUE, the result is
equal to the value of Integer.MIN_VALUE.
If the argument is positive infinity or any value greater than or equal to the value of Integer.MAX_VALUE, the result is
equal to the value of Integer.MAX_VALUE. // From JDK api documentation

Q27)
1 Boolean b1 = new Boolean("TRUE");
2 Boolean b2 = new Boolean("true");
3 Boolean b3 = new Boolean("JUNK");
4 System.out.println("" + b1 + b2 + b3);
a) Comiler error
b) RunTime error
c)truetruefalse
d)truetruetrue
Correct answer is c)

Q28) In the above question if line 4 is changed to
System.out.println(b1+b2+b3); The output is
a) Compile time error
b) Run time error
c) truetruefalse
d) truetruetrue
Correct answer is a) As there is no method to support Boolean + Boolean
Boolean b1 = new Boolean("TRUE");
Think ----->System.out.println(b1); // Is this valid or not?

Q29. What is the output
{
Float f1 = new Float("4.4e99f");
Float f2 = new Float("-4.4e99f");
Double d1 = new Double("4.4e99");
System.out.println(f1);
System.out.println(f2);
System.out.println(d1);
}
a) Runtime error
b) Infinity
-Infinity
4.4E99
c) Infinity
-Infinity
Infinity
d) 4.4E99
-4.4E99
4.4E99
Correct answer is b)

Q30 Q. Which of the following wrapper classes can not
take a "String" in constructor
1) Boolean
2) Integer
3) Long
4) Character
5) Byte
6) Short
correct answer is 4)

Q31. What is the output of following
Double d2 = new Double("-5.5");
Double d3 = new Double("-5.5");
System.out.println(d2==d3);
System.out.println(d2.equals(d3));
a) true
true
b) false
false
c) true
false
d) false
true
Correct answer is d)

Q32) Which one of the following always honors the components's preferred size.
a) FlowLayout
b) GridLayout
c) BorderLayout
Correct answer is a)
Q33) Look at the following code
import java.awt.*;
public class visual extends java.applet.Applet{
static Button b = new Button("TEST");
public void init(){
add(b);
}
public static void main(String args[]){
Frame f = new Frame("Visual");
f.setSize(300,300);
f.add(b);
f.setVisible(true);
}
}
What will happen if above code is run as a standalone application
a) Displays an empty frame
b) Displays a frame with a button covering the entire frame
c) Displays a frame with a button large enough to accomodate its label.
Correct answer is b) Reason- Frame uses Border Layout which places the button to CENTRE
(By default) and ignores Button's preferred size.
Q34 If the code in Q33 is compiled and run via appletviewer what will happen
a) Displays an empty applet
b) Displays a applet with a button covering the entire frame
c) Displays a applet with a button large enough to accomodate its label.
Correct answer is c) Reason- Applet uses FlowLayout which honors Button's preferred size.

Q35. What is the output
public static void main(String args[]){
Frame f = new Frame("Visual");
f.setSize(300,300);
f.setVisible(true);
Point p = f.getLocation();
System.out.println("x is " + p.x);
System.out.println("y is " + p.y);
}
a) x is 300
y is 300
b) x is 0
y is 0
c) x is 0
y is 300
correct answer is b) Because postion is always relative to parent container and in this
case Frame f is the topemost container

Q36) Which one of the following always ignores the components's preferred size.
a) FlowLayout
b) GridLayout
c) BorderLayout
Correct answer is b)
Q37) Consider a directory structure like this (NT or 95)
C:\JAVA\12345.msg --FILE
\dir1\IO.class -- IO.class is under dir1
Consider the following code
import java.io.*;
public class IO {
public static void main(String args[]) {
File f = new File("..\\12345.msg");
try{
System.out.println(f.getCanonicalPath());
System.out.println(f.getAbsolutePath());
}catch(IOException e){
System.out.println(e);
}
}
}
What will be the output of running "java IO" from C:\java\dir1
a) C:\java\12345.msg
C:\java\dir1\..\12345.msg
b) C:\java\dir1\12345.msg
C:\java\dir1\..\12345.msg
c) C:\java\dir1\..\12345.msg
C:\java\dir1\..\12345.msg
correct answer is a) as getCanonicalPath Returns the canonical form of this File object's pathname. The precise definition of canonical form is system-dependent, but it usually
specifies an absolute pathname in which all relative references and references to the current user directory have been completely resolved.
WHERE AS
getAbsolutePath Returns the absolute pathname of the file represented by this object. If this object represents an absolute pathname, then return the pathname. Otherwise, return a pathname that is a concatenation of the current user directory, the separator character, and the pathname of this file object.

Q38) Suppose we copy IO.class from C:\java\dir1 to c:\java
What will be the output of running "java IO" from C:\java.
a) C:\java\12345.msg
C:\java\..\12345.msg
b) C:\12345.msg
C:\java\..\12345.msg
c) C:\java\..\12345.msg
C:\java\\..\12345.msg
correct answer is b)

Q39) Which one of the following methods of java.io.File throws IOException and why
a) getCanonicalPath and getAbsolutePath both require filesystem queries.
b) Only getCannonicalPath as it require filesystem queries.
c) Only getAbsolutePath as it require filesystem queries.
Correct answer is b)
Q40) What will be the output if
Consider a directory structure like this (NT or 95)
C:\JAVA\12345.msg --FILE
\dir1\IO.class -- IO.class is under dir1
import java.io.*;
public class IO {
public static void main(String args[]) {
File f = new File("12345.msg");
String arr[] = f.list();
System.out.println(arr.length);
}
}
a) Compiler error as 12345.msg is a file not a directory
b) java.lang.NullPointerException at run time
c) No error , but nothing will be printed on screen
Correct ansewer is b)
Q41) What will be the output
Consider a directory structure like this (NT or 95)
C:\JAVA\12345.msg --FILE
import java.io.*;
public class IO {
public static void main(String args[]) {
File f1 = new File("\\12345.msg");
System.out.println(f1.getPath());
System.out.println(f1.getParent());
System.out.println(f1.isAbsolute());
System.out.println(f1.getName());
System.out.println(f1.exists());
System.out.println(f1.isFile());
}
}
a) \12345.msg
\
true
12345.msg
true
true
b) \12345.msg
\
true
\12345.msg
false
false
c) 12345.msg
\
true
12345.msg
false
false
d) \12345.msg
\
true
12345.msg
false
false
correct answer is d)
Q42) If in question no 41 the line
File f1 = new File("\\12345.msg"); is replaced with File f1 = new File("12345.msg");
What will be the output
a) 12345.msg
\
true
12345.msg
true
true
b) 12345.msg
null
true
12345.msg
true
true

c) 12345.msg
null
false
12345.msg
true
true
d) \12345.msg
\
true
12345.msg
false
false

Correct answer is c)

Java Certification Model Question & Answer - 3
________________________________________
1. Which declarations are true about inner classes?
A. new InnerClass(){
B. public abstract class Innerclass{
C. new Ineerclass() extends Mainclass{
2. Which access modifier is used to restrict the methods scope to itself and still allows other classes to subclass that class?
A. private
B. final
C. protected
D. friend
3. Which one of the following will equate to true?
Float f1 = new Float(0.9f);
Float f2 = new Float(0.9f);
Double d = new Double(0.9);
A. f1 == f2;
B. f2 == d;
C. f1.equals(f2);
D. f2.equals(f1)
E. f2.equals(d); // will return false not error
4. Which statement below is true regarding the above code?
The following shows class hierarchy
Derived1 , Derived2 extends from Mainclass.
Mainclass m;
Derived1 one;
Derived2 two;
one = (Derived1) m;
A. Compilation error
B. Comiplation is legal but generates runtime error
C. Compilation is legal but generates ClassCastException during execution
D. Compilation is legal probably okay during execution
5. What will be printed when the follwoing code is executed?
outer : for(int i =1; i<3 ; i++){
inner : for ( int j = 1;j 0){
System.out.println("i is "+i);
}
System.out.println("Finished");
}
What will be the output of the above code?
A. i is 0
B. Infinite loop
C. Finished
D. i is 1
23. getID() method of AWTEvent refers to what?
Nature or Type of Event
24. What are the correct declarations for 2 dimensional ararys?
A. int a[][] = new int[4,4];
B. int []a[] = new int[4][4];
C. int a[][] = new int[4][4];
D. int a[4][4] = new int[][];
E. int [][]a = new int[4][4];
25. What causes current thread to stop executing?( which statements are true about thread?)
A. Threads created from same class finish together
B. Thread can be created only by subclassing java.lang.Thread
C. Thread execution of specific thread can be suspended indefinitely if required.
D. Java interpreter exits when main thread exits even if the other threads are running.
E. Uncoordination of multiple threads will affect data integrity .
26. What statements are true about gc?
A. gc releases memory at predictable rates.
B. gc requires additional code in case multiple threads are running
C. Programmer has a mechanism that explicitly & immediately frees memory used by java objects
D. gc system never reclaims memory from objects which are still accessible to a running user thread
27. What are true about Listeners?
A. Return value is boolean
B. Most components allow multiple listeners to be added
C. A copy of original event passed to listener method
D. Multiple listeners added to single component, they must be made friends
E. The order of invocation of the listener is specified to be in which they are added
28. What is the correct way of declaring native methods?
A. public abstract native method() {}
B. public native void method();
C. native void method(){}
D. public native void method() {}
29. What are the java keywords?
A. friendly
B. extends
C. synchronized
D. sizeof
E. interfaceof
30. What is the range for char variable?
0 to 216-1
31. What is the range for int variable?
-231 to 231-1
32. Which are valid java identifiers?
A. thisfinal
B. %great
C. intern
D. 3fun
A. z_fal
33. The main method for class Test is given below:
try{
state();
}
catch(ArithmeticException ex)
{
System.out.println("Arithmetic");
}
finally{
Sytem.out.println("finally");
}
System.out.println("done");
What will be the output of the above code (Choose the correct one) if method state() throws NullPointerException?
A. Arithmetic
B. finally
C. done
D. Exception not caught
34. At what point will the String referenced at line 1 is available for garbage collection in this method?
1. String s1 = "abc";
2. String s2 = "bdc";
3. s1.concat(s2);
4. s1 = null;
5. s1 += s2;
6. System.out.println(s1);
A. Just Before 4
B. Just Before 5
C. Just Before 6
D. never
35. Which cannot be added to Container?
A. Applet
B. Panel
C. Container
D. MenuComponent
36. Which of the following code statement will throw NullPointerException
String s = "hello";
s == null;
a. if(s != null & s.length() >0)
b. if(s == null && s.length() >0)
c. if(s != null || s.length() >0)
d. if(s == null | s.length() >0)
37. which of the following are true?
class x {
int x;
public static void main(String args[]) {
x = 10;
System.out.println(" value of x "+x);
}
}
a. prints "value of x 10"
b. compilation error
c. Runtime Error
38. what are the valid codes that come in //Point X place declared in Test.java
// Point X
public class Test {}
a. import java.awt.*;
b. package local.util;
c. class someclass {}
d. protected class myclass {}
e. private static final int more = 1000;
39. Which of the following evaluate to true?
float f = 10.0f
long l = 10L
a. f == 10.0f
b. f = 10.0 // 10.0 is a double value
c. f == 10.0 // converted to parent class, here double
d. f == l
e. l == 10.0
40. FilterInputStream is subclassed by DataInputStream, BufferedInputStream, ByteArrayInputStream.
What is the valid argument for FilterInputStream constructor?
a. File
b. FileInputStream
c. PrintStream
d. BufferedReader

1. Which of the following are valid definitions of an application's main( ) method?

a) public static void main();
b) public static void main( String args );
c) public static void main( String args[] );
d) public static void main( Graphics g );
e) public static boolean main( String args[] );

2. If MyProg.java were compiled as an application and then run from the command line as:
java MyProg I like tests
what would be the value of args[ 1 ] inside the main( ) method?

a) MyProg
b) "I"
c) "like"
d) 3
e) 4
f) null until a value is assigned

3. Which of the following are Java keywords?

a) array
b) boolean
c) Integer
d) protect
e) super

4. After the declaration:
char[] c = new char[100];
what is the value of c[50]?

a) 50
b) 49
c) '\u0000'
d) '\u0020'
e) " "
f) cannot be determined
g) always null until a value is assigned

5. After the declaration:
int x;
the range of x is:

a) -231 to 231-1
b) -216 to 216 - 1
c) -232 to 232
d) -216 to 216
e) cannot be determined; it depends on the machine

6. Which identifiers are valid?

a) _xpoints
b) r2d2
c) bBb$
d) set-flow
e) thisisCrazy

7. Represent the number 6 as a hexadecimal literal.

8. Which of the following statements assigns "Hello Java" to the String variable s?

a) String s = "Hello Java";
b) String s[] = "Hello Java";
c) new String s = "Hello Java";
d) String s = new String("Hello Java");

9. An integer, x has a binary value (using 1 byte) of 10011100. What is the binary value of z after these statements:
int y = 1 <> performs signed shift while >>> performs an unsigned shift.
b) >>> performs a signed shift while >> performs an unsigned shift.
c) << performs a signed shift while <<< performs an insigned shift.
d) <<< performs a signed shift while << performs an unsigned shift.

11. The statement ...
String s = "Hello" + "Java";
yields the same value for s as ...
String s = "Hello";
String s2= "Java";
s.concat( s2 );
True
False

12. If you compile and execute an application with the following code in its main() method:
String s = new String( "Computer" );

if( s == "Computer" )

System.out.println( "Equal A" );

if( s.equals( "Computer" ) )

System.out.println( "Equal B" );
a) It will not compile because the String class does not support the = = operator.
b) It will compile and run, but nothing is printed.
c) "Equal A" is the only thing that is printed.
d) "Equal B" is the only thing that is printed.
e) Both "Equal A" and "Equal B" are printed.

13. Consider the two statements:
1. boolean passingScore = false && grade == 70;

2. boolean passingScore = false & grade == 70;
The expression
grade == 70
is evaluated:

a) in both 1 and 2
b) in neither 1 nor 2
c) in 1 but not 2
d) in 2 but not 1
e) invalid because false should be FALSE

14. Given the variable declarations below:
byte myByte;
int myInt;
long myLong;
char myChar;
float myFloat;
double myDouble;
Which one of the following assignments would need an explicit cast?

a) myInt = myByte;
b) myInt = myLong;
c) myByte = 3;
d) myInt = myChar;
e) myFloat = myDouble;
f) myFloat = 3;
g) myDouble = 3.0;

15. Consider this class example:
class MyPoint

{ void myMethod()

{ int x, y;

x = 5; y = 3;

System.out.print( " ( " + x + ", " + y + " ) " );

switchCoords( x, y );

System.out.print( " ( " + x + ", " + y + " ) " );

}

void switchCoords( int x, int y )

{ int temp;

temp = x;

x = y;

y = temp;

System.out.print( " ( " + x + ", " + y + " ) " );

}

}
What is printed to standard output if myMethod() is executed?

a) (5, 3) (5, 3) (5, 3)
b) (5, 3) (3, 5) (3, 5)
c) (5, 3) (3, 5) (5, 3)

16. To declare an array of 31 floating point numbers representing snowfall for each day of March in Gnome, Alaska, which declarations would be valid?

a) double snow[] = new double[31];
b) double snow[31] = new array[31];
c) double snow[31] = new array;
d) double[] snow = new double[31];

17. If arr[] contains only positive integer values, what does this function do?
public int guessWhat( int arr[] )

{ int x= 0;

for( int i = 0; i < arr.length; i++ )

x = x < arr[i] ? arr[i] : x;

return x;

}
a) Returns the index of the highest element in the array
b) Returns true/false if there are any elements that repeat in the array
c) Returns how many even numbers are in the

1) What is the Vector class?
ANSWER : The Vector class provides the capability to implement a growable array of objects.
2) What is the Set interface?
ANSWER : The Set interface provides methods for accessing the elements of a finite mathematical set.Sets do not allow duplicate elements.
3) What is Dictionary class?
ANSWER : The Dictionary class is the abstarct super class of Hashtable and Properties class.Dictionary provides the abstarct functions used to store and retrieve objects by key-value.This class allows any object to be used as a key or value.
4) What is the Hashtable class?
ANSWER : The Hashtable class implements a hash table data structure. A hash table indexes and stores objects in a dictionary using hash codes as the objects' keys. Hash codes are integer values that identify objects.
5) What is the Properties class?
Answer : The properties class is a subclass of Hashtable that can be read from or written to a stream.It also provides the capability to specify a set of default values to be used if a specified key is not found in the table. We have two methods load() and save().
6) What changes are needed to make the following prg to compile?
import java.util.*;
class Ques{
public static void main (String args[]) {
String s1 = "abc";
String s2 = "def";
Vector v = new Vector();
v.add(s1);
v.add(s2);
String s3 = v.elementAt(0) + v.elementAt(1);
System.out.println(s3);
}
}
ANSWER : Declare Ques as public B) Cast v.elementAt(0) to a String
C) Cast v.elementAt(1) to an Object. D) Import java.lang
ANSWER : B) Cast v.elementAt(0) to a String

8) What is the output of the prg.
import java.util.*;
class Ques{
public static void main (String args[]) {
String s1 = "abc";
String s2 = "def";
Stack stack = new Stack();
stack.push(s1);
stack.push(s2);
try{
String s3 = (String) stack.pop() + (String) stack.pop() ;
System.out.println(s3);
}catch (EmptyStackException ex){}
}
}
ANSWER : abcdef B) defabc C) abcabc D) defdef
ANSWER : B) defabc
9) Which of the following may have duplicate elements?
ANSWER : Collection B) List C) Map D) Set
ANSWER : A and B Neither a Map nor a Set may have duplicate elements.
10) Can null value be added to a List?
ANSWER : Yes.A Null value may be added to any List.
11) What is the output of the following prg.
import java.util.*;
class Ques{
public static void main (String args[]) {
HashSet set = new HashSet();
String s1 = "abc";
String s2 = "def";
String s3 = "";
set.add(s1);
set.add(s2);
set.add(s1);
set.add(s2);
Iterator i = set.iterator();
while(i.hasNext())
{
s3 += (String) i.next();
}
System.out.println(s3);
}
}
A) abcdefabcdef B) defabcdefabc C) fedcbafedcba D) defabc
ANSWER : D) defabc. Sets may not have duplicate elements.
12) Which of the following java.util classes support internationalization?
A) Locale B) ResourceBundle C) Country D) Language
ANSWER : A and B . Country and Language are not java.util classes.
13) What is the ResourceBundle?
A. The ResourceBundle class also supports internationalization.
ResourceBundle subclasses are used to store locale-specific resources that can be loaded by a program to tailor the program's appearence to the paticular locale in which it is being run. Resource Bundles provide the capability to isolate a program's locale-specific resources in a standard and modular manner.
14) How are Observer Interface and Observable class, in java.util package, used?
ANSWER : Objects that subclass the Observable class maintain a list of Observers. When an Observable object is updated it invokes the update() method of each of its observers to notify the observers that it has changed state. The Observer interface is implemented by objects that observe Observable objects.
15) Which java.util classes and interfaces support event handling?
ANSWER : The EventObject class and the EventListener interface support event processing.
16) Does java provide standard iterator functions for inspecting a collection of objects?
ANSWER : The Enumeration interface in the java.util package provides a framework for stepping once through a collection of objects. We have two methods in that interface.
public interface Enumeration {
boolean hasMoreElements();
Object nextElement();
}
17) The Math.random method is too limited for my needs- How can I generate random numbers more flexibly?
ANSWER : The random method in Math class provide quick, convienient access to random numbers, but more power and flexibility use the Random class in the java.util package.
double doubleval = Math.random();
The Random class provide methods returning float, int, double, and long values.
nextFloat() // type float; 0.0 <= value < 1.0
nextDouble() // type double; 0.0 <= value < 1.0
nextInt() // type int; Integer.MIN_VALUE <= value <= Integer.MAX_VALUE
nextLong() // type long; Long.MIN_VALUE <= value Generic Servlet-->HttpServlet-->MyServlet.
The Servlet interface declares, but does not implement, methods that manage the servlet and its communications with clients. Servlet writers provide some or all of these methods when developing a servlet.
6) When a servlet accepts a call from a client, it receives two objects- What are they?
ANSWER : ServeltRequest: Which encapsulates the communication from the client to the server.
ServletResponse: Whcih encapsulates the communication from the servlet back to the client.
ServletRequest and ServletResponse are interfaces defined by the javax.servlet package.
7) What information that the ServletRequest interface allows the servlet access to?
ANSWER : Information such as the names of the parameters passed in by the client, the protocol (scheme) being used by the client, and the names of the remote host that made the request and the server that received it.
The input stream, ServletInputStream.Servlets use the input stream to get data from clients that use application protocols such as the HTTP POST and PUT methods.
8) What information that the ServletResponse interface gives the servlet methods for replying to the client?
ANSWER : It Allows the servlet to set the content length and MIME type of the reply.
Provides an output stream, ServletOutputStream and a Writer through which the servlet can send the reply data.
9) What is the servlet Lifecycle?
ANSWER : Each servlet has the same life cycle:
A server loads and initializes the servlet (init())
The servlet handles zero or more client requests (service())
The server removes the servlet (destroy())
(some servers do this step only when they shut down)
10) How HTTP Servlet handles client requests?
ANSWER : An HTTP Servlet handles client requests through its service method. The service method supports standard HTTP client requests by dispatching each request to a method designed to handle that request. 1
Definitions

1. Encapsulation :
Encapsulation is the mechanism that binds together code and the data it manipulates and keeps both safe from outside interference and misuse.
2. Inheritance:
Inheritance is the process by which one object acquires the properties of another object.
3. Polymorphism:
Polymorphism is a feature that allows one interface to be used for a general class of actions. The specific action is determined by the exact nature of actions.
4. Code Blocks:
Two or more statements which is allowed to be grouped into blocks of code is otherwise called as Code Blocks.This is done by enclosing the statements between opening and closing curly braces.
5. Floating-point numbers:
Floating-point numbers which is also known as real numbers, are used when evaluating expressions that require fractional precision.
6. Unicode:
Unicode defines a fully international character set that can represent all of the characters found in all human languages. It is a unification of dozens of character sets, such as Latin, Greek, Arabic and many more.
7. Booleans:
Java has a simple type called boolean, for logical values. It can have only on of two possible values, true or false.
8. Casting:
A cast is simply an explicit type conversion. To create a conversion between two incompatible types, you must use a cast.
9. Arrays:
An array is a group of like-typed variables that are referred to by a common name. Arrays offer a convenient means of grouping related information. Arrays of any type can be created and may have one or more dimension.
10. Relational Operators:
The relational operators determine the relationship that one operand has to the other. They determine the equality and ordering.
11.Short-Circuit Logical Operators:
The secondary versions of the Boolean AND and OR operators are known as short-
circuit logical operators. It is represented by || and &&..
12. Switch:
The switch statement is Java’s multiway branch statement. It provides an easy way to
dispatch execution to different parts of your code based on the value of an
experession.
13. Jump Statements:
Jump statements are the statements which transfer control to another part of your
program. Java Supports three jump statements: break, continue, and return.
14. Instance Variables:
The data, or variable, defined within a class are called instance variable.
Which of the following class defines a legal abstract class ?
a. class Animal { abstract void grow1( ); }
b. adstract Animal { abstract void grow1( ); }
c. class abstract Animal { abstract void grow1( ); }
d. abstract class Animal { abstract void grow1( ); }
e. abstract class Animal { abstract void grow1( );
{ System.out.println(grow1); } }
For an object to be a target foe a thread, that object must be of type ________
What is the proper way of defining a class named key so that it cannot be subclassed ?
a. class Key { }
b. abstract final class Key { }
c. native class Key { }
d. class Key { final: }
e. final class key { }
What modes are legal for creating a new RandomAccessFile object ?
a. w
b. r
c. x
d. rw
e. xrw
In RMI, Using which class to create ServerSide Object.
a. ServerSocket
b. Server
c. UnicastRemoteObject
d. MulicastSocket
In RMI application, using whaic object to interact with Server object from the Client Object.
a. Remote
b. RMIServer
c. Skeleton
d. Stub
In RMI which class is using to bind the Server

Questions on Language Fundamentals
1. Which of these are legal identifiers. Select all the correct answers.
A. number_1
B. number_a
C. $1234
D. -volatile
2. Which of these are not legal identifiers. Select all the correct answers.
A. 1alpha
B. _abcd
C. xy+abc
D. transient
E. account-num
F. very_long_name
3. Which of the following are keywords in Java. Select all the correct answers.
A. friend
B. NULL
C. implement
D. synchronized
E. throws
4. Which of the following are Java keywords. Select all the correct answers.
A. super
B. strictfp
C. void
D. synchronize
E. instanceof
5. Which of these are Java keywords. Select all the correct answers
A. TRUE
B. volatile
C. transient
D. native
E. interface
F. then
G. new
6. Using up to four characters, write the Java representation of octal literal 6.
7. Using up to four characters, write the Java representation of integer literal 3 in hexadecimal.
8. Using up to four characters, write the Java representation of integer literal 10 in hexadecimal.
9. What is the minimum value of char type. Select the one correct answer.
A. 0
B. -215
C. -28
D. -215 - 1
E. -216
F. -216 - 1
10. How many bytes are used to represent the primitive data type int in Java. Select the one correct answer.
A. 2
B. 4
C. 8
D. 1
E. The number of bytes to represent an int is compiler dependent.
11. What is the legal range of values for a variable declared as a byte. Select the one correct answer.
A. 0 to 256
B. 0 to 255
C. -128 to 127
D. -128 to 128
E. -127 to 128
F. -215 to 215 - 1
12. The width in bits of double primitive type in Java is --. Select the one correct answer.
A. The width of double is platform dependent
B. 64
C. 128
D. 8
E. 4
13. What would happen when the following is compiled and executed. Select the one correct answer.
14.
15. public class Compare {
16. public static void main(String args[]) {
17. int x = 10, y;
18. if(x = 10) y = 2;
21. System.out.println("y is " + y);
22. }
23. }
24.
A. The program compiles and prints y is 0 when executed.
B. The program compiles and prints y is 1 when executed.
C. The program compiles and prints y is 2 when executed.
D. The program does not compile complaining about y not being initialized.
E. The program throws a runtime exception.
25. What would happen when the following is compiled and executed. Select the one correct answer.
26.
27. class example {
28. int x;
29. int y;
30. String name;
31. public static void main(String args[]) {
32. example pnt = new example();
33. System.out.println("pnt is " + pnt.name +
34. " " + pnt.x + " " + pnt.y);
35. }
36. }
37.
A. The program does not compile because x, y and name are not initialized.
B. The program throws a runtime exception as x, y, and name are used before initialization.
C. The program prints pnt is 0 0.
D. The program prints pnt is null 0 0.
E. The program prints pnt is NULL false false
38. The initial value of an instance variable of type String which is not explicitly initialized in the program is --. Select the one correct answer.
A. null
B. ""
C. NULL
D. 0
E. The instance variable must be explicitly assigned.
39. The initial value of a local variable of type String which is not explicitly initialized and which is defined in a member function of a class. Select all the correct answer.
A. null
B. ""
C. NULL
D. 0
E. The local variable must be explicitly assigned.
40. Which of the following are legal Java programs. Select all the correct answer.
A. // The comments come before the package
package pkg;
import java.awt.*;
class C{};
B. package pkg;
import java.awt.*;
class C{};
C. package pkg1;
package pkg2;
import java.awt.*;
class C{};
D. package pkg;
import java.awt.*;
E. import java.awt.*;
class C{};
F. import java.awt.*;
package pkg;
class C {};
41. Which of the following statements are correct. Select all correct answers.
A. A Java program must have a package statement.
B. A package statement if present must be the first statement of the program
C. If a Java program defines both a package and import statement, then the import statement must come before the package statement.
D. An empty file is a valid source file.
E. A Java file without any class or interface definitions can also be compiled.
F. If an import statement is present, it must appear before any class or interface definitions.
42. What would be the results of compiling and running the following class. Select the one correct answer.
43.
44. class test {
45. public static void main() {
46. System.out.println("test");
47. }
48. }
49.
A. The program does not compile as there is no main method defined.
B. The program compiles and runs generating an output of "test"
C. The program compiles and runs but does not generate any output.
D. The program compiles but does not run.
50. Which of these are valid declarations for the main method? Select all correct answers.
A. public void main();
B. static void main(String args[]);
C. public static void main(String args[]);
D. static public void main(String);
E. public static void main(String );
F. public static int main(String args[]);
51. Which of the following are valid declarations for the main method. Select all correct answers.
A. public static void main(String args[]);
B. public static void main(String []args);
C. final static public void main (String args[]);
D. public static int main(String args[]);
E. public static abstract void main(String args[]);
52. What happens when the following program is compiled and executed with the arguments - java test. Select the one correct answer.
53.
54. class test {
55. public static void main(String args[]) {
56. if(args.length > 0)
57. System.out.println(args.length);
58. }
59. }
60.
A. The program compiles and runs but does not print anything.
B. The program compiles and runs and prints 0
C. The program compiles and runs and prints 1
D. The program compiles and runs and prints 2
E. The program does not compile.
61. What is the result of compiling and running this program ? Select the one correct answer.
62.
63. public class test {
64. public static void main(String args[]) {
65. int i, j;
66. int k = 0;
67. j = 2;
68. k = j = i = 1;
69. System.out.println(k);
70. }
71. }
72.
73.
A. The program does not compile as k is being read without being initialized.
B. The program does not compile because of the statement k = j = i = 1;
C. The program compiles and runs printing 0.
D. The program compiles and runs printing 1.
E. The program compiles and runs printing 2.
74. What gets printed on the standard output when the class below is compiled and executed by entering "java test lets see what happens". Select the one correct answer.
75.
76. public class test {
77. public static void main(String args[]) {
78. System.out.println(args[0] + " " + args[args.length - 1]);
79. }
80. }
81.
A. The program will throw an ArrayIndexOutOfBounds exception.
B. The program will print "java test"
C. The program will print "java hapens";
D. The program will print "test happens"
E. The program will print "lets happens"
82. What gets printed on the standard output when the class below is compiled and executed by entering "java test lets see what happens". Select the one correct answer.
83.
84. public class test {
85. public static void main(String args[]) {
86. System.out.println(args[0] + " " + args[args.length]);
87. }
88. }
89.
A. The program will throw an ArrayIndexOutOfBounds exception.
B. The program will print "java test"
C. The program will print "java hapens";
D. The program will print "test happens"
E. The program will print "lets happens"
90. What all gets printed on the standard output when the class below is compiled and executed by entering "java test lets see what happens". Select all correct answers.
91.
92. public class test {
93. public static void main(String args[]) {
94. System.out.println(args[0] + " " + args.length);
95. }
96. }
97.
A. java
B. test
C. lets
D. 3
E. 4
F. 5
G. 6
98. What happens when the following program is compiled and run. Select the one correct answer.
99.
100. public class example {
101. int i = 0;
102. public static void main(String args[]) {
103. int i = 1;
104. i = change_i(i);
105. System.out.println(i);
106. }
107. public static int change_i(int i) {
108. i = 2;
109. i *= 2;
110. return i;
111. }
112. }
113.
A. The program does not compile.
B. The program prints 0.
C. The program prints 1.
D. The program prints 2.
E. The program prints 4.
114. What happens when the following program is compiled and run. Select the one correct answer.
115.
116. public class example {
117. int i = 0;
118. public static void main(String args[]) {
119. int i = 1;
120. change_i(i);
121. System.out.println(i);
122. }
123. public static void change_i(int i) {
124. i = 2;
125. i *= 2;
126. }
127. }
128.
A. The program does not compile.
B. The program prints 0.
C. The program prints 1.
D. The program prints 2.
E. The program prints 4.
129. What happens when the following program is compiled and run. Select the one correct answer.
130.
131. public class example {
132. int i[] = {0};
133. public static void main(String args[]) {
134. int i[] = {1};
135. change_i(i);
136. System.out.println(i[0]);
137. }
138. public static void change_i(int i[]) {
139. i[0] = 2;
140. i[0] *= 2;
141. }
142. }
143.
A. The program does not compile.
B. The program prints 0.
C. The program prints 1.
D. The program prints 2.
E. The program prints 4.
144. What happens when the following program is compiled and run. Select the one correct answer.
145.
146. public class example {
147. int i[] = {0};
148. public static void main(String args[]) {
149. int i[] = {1};
150. change_i(i);
151. System.out.println(i[0]);
152. }
153. public static void change_i(int i[]) {
154. int j[] = {2};
155. i = j;
156. }
157. }
158.
A. The program does not compile.
B. The program prints 0.
C. The program prints 1.
D. The program prints 2.
E. The program prints 4.

________________________________________
Answers to questions on Language Fundamentals
6. a, b, c
7. a, c, d, e
8. d, e
9. a, b, c, e
10. b, c, d, e, g
11. Any of the following are correct answers - 06, 006, or 0006
12. Any of the following are correct answers - 0x03, 0X03, 0X3 or 0x3
13. Any of the following are correct answers - 0x0a, 0X0a, 0Xa, 0xa, 0x0A, 0X0A, 0XA, 0xA
14. a
15. b
16. c
17. b
18. d. The variable y is getting read before being properly initialized.
19. d. Instance variable of type int and String are initialized to 0 and NULL respectively.
20. a
21. e
22. a, b, d, e
23. b, d, e, f
24. d
25. b, c
26. a, b, c
27. a
28. d
29. e
30. a
31. c, e
32. e
33. c
34. e
35. c

Questions on Operator and Assignments
1. In the following class definition, which is the first line (if any) that causes a compilation error. Select the one correct answer.
2.
3. pubic class test {
4. public static void main(String args[]) {
5. char c;
6. int i;
7. c = 'A'; // 1
8. i = c; //2
9. c = i + 1; //3
10. c++; //4
11. }
12. }
13.
A. The line labeled 1.
B. The line labeled 2.
C. The line labeled 3.
D. The line labeled 4.
E. All the lines are correct and the program compiles.
14. Which of these assignments are valid. Select all correct answers.
A. short s = 28;
B. float f = 2.3;
C. double d = 2.3;
D. int I = '1';
E. byte b = 12;
15. What gets printed when the following program is compiled and run. Select the one correct answer.
16.
17. class test {
18. public static void main(String args[]) {
19. int i,j,k,l=0;
20. k = l++;
21. j = ++k;
22. i = j++;
23. System.out.println(i);
24. }
25. }
26.
A. 0
B. 1
C. 2
D. 3
27. Which of these lines will compile? Select all correct answers.
A. short s = 20;
B. byte b = 128;
C. char c = 32;
D. double d = 1.4;;
E. float f = 1.4;
F. byte e = 0;
28. The signed right shift operator in Java is --. Select the one correct answer.
A. <>
C. >>>;
D. None of these.
29. What gets printed on the standard output when the class below is compiled and executed. Select the one correct answer.
30.
31. public static ShortCkt {
32. public static void main(String args[]) {
33. int i = 0;
34. boolean t = true;
35. boolean f = false, b;
36. b = (t && ((i++) == 0));
37. b = (f && ((i+=2) > 0));
38. System.out.println(i);
39. }
40. }
41.
A. 0
B. 1
C. 2
D. 3
42. What gets printed on the standard output when the class below is compiled and executed. Select the one correct answer.
43.
44. public static ShortCkt {
45. public static void main(String args[]) {
46. int i = 0;
47. boolean t = true;
48. boolean f = false, b;
49. b = (t & ((i++) == 0));
50. b = (f & ((i+=2) > 0));
51. System.out.println(i);
52. }
53. }
54.
A. 0
B. 1
C. 2
D. 3
55. What gets printed on the standard output when the class below is compiled and executed. Select the one correct answer.
56.
57. public static ShortCkt {
58. public static void main(String args[]) {
59. int i = 0;
60. boolean t = true;
61. boolean f = false, b;
62. b = (t || ((i++) == 0));
63. b = (f || ((i+=2) > 0));
64. System.out.println(i);
65. }
66. }
67.
A. 0
B. 1
C. 2
D. 3
68. What gets printed on the standard output when the class below is compiled and executed. Select the one correct answer.
69.
70. public static ShortCkt {
71. public static void main(String args[]) {
72. int i = 0;
73. boolean t = true;
74. boolean f = false, b;
75. b = (t | ((i++) == 0));
76. b = (f | ((i+=2) > 0));
77. System.out.println(i);
78. }
79. }
80.
A. 0
B. 1
C. 2
D. 3
81. Which operator is used to perform bitiwse inversion in Java. Select the one correct answer.
A. ~
B. !
C. &
D. |
E. ^
82. What gets printed when the following program is compiled and run. Select the one correct answer.
83.
84.
85. public class test {
86. public static void main(String args[]) {
87. byte x = 3;
88. x = (byte)~x;
89. System.out.println(x);
90. }
91. }
92.
93.
A. 3
B. 0
C. 1
D. 11
E. 252
F. 214
G. 124
H. -4
94. What gets displayed on the screen when the following program is compiled and run. Select the one correct answer.
95.
96. public class test {
97. public static void main(String args[]) {
98. int x,y;
99. x = 3 & 5;
100. y = 3 | 5;
101. System.out.println(x + " " + y);
102. }
103. }
104.
A. 7 1
B. 3 7
C. 1 7
D. 3 1
E. 1 3
F. 7 3
G. 7 5
105. What gets displayed on the screen when the following program is compiled and run. Select the one correct answer.
106.
107. public class test {
108. public static void main(String args[]) {
109. int x,y;
110. x = 1 & 7;
111. y = 3 ^ 6;
112. System.out.println(x + " " + y);
113. }
114. }
115.
A. 1 3
B. 3 5
C. 5 1
D. 3 6
E. 1 7
F. 1 5
116. Which operator is used to perform bitwise exclusive or.
A. &
B. ^
C. |
D. !
E. ~
117. What gets displayed on the screen when the following program is compiled and run. Select the one correct answer.
118.
119. public class test {
120. public static void main(String args[]) {
121. boolean x = true;
122. int a;
123. if(x) a = x ? 1: 2;
124. else a = x ? 3: 4;
125. System.out.println(a);
126. }
127. }
128.
A. 1
B. 2
C. 3
D. 4
129. What gets displayed on the screen when the following program is compiled and run. Select the one correct answer.
130.
131. public class test {
132. public static void main(String args[]) {
133. boolean x = false;
134. int a;
135. if(x) a = x ? 1: 2;
136. else a = x ? 3: 4;
137. System.out.println(a);
138. }
139. }
140.
A. 1
B. 2
C. 3
D. 4
141. What gets displayed on the screen when the following program is compiled and run. Select the one correct answer.
142.
143. public class test {
144. public static void main(String args[]) {
145. int x, y;
146.
147. x = 5 >> 2;
148. y = x >>> 2;
149. System.out.println(y);
150. }
151. }
152.
A. 5
B. 2
C. 80
D. 0
E. 64
153. What gets displayed on the screen when the following program is compiled and run. Select the one correct answer.
154.
155. public class test {
156. public static void main(String args[]) {
157. int x;
158.
159. x = -3 >> 1;
160. x = x >>> 2;
161. x = x << 1;
162. System.out.println(x);
163. }
164. }
165.
A. 1
B. 0
C. 7
D. 5
E. 23
F. 2147483646
166. Which of the following are correct. Select all correct answers.
A. Java provides two operators to do left shift - << and <> is the zero fill right shift operator.
C. >>> is the signed right shift operator.
D. For positive numbers, results of p[erators >> and >>> are same.
167. What is the result of compiling and running the following program. Select one correct answer.
168.
169. public class test {
170. public static void main(String args[]) {
171. int i = -1;
172. i = i >> 1;
173. System.out.println(i);
174. }
175. }
176.
A. 63
B. -1
C. 0
D. 1
E. 127
F. 128
G. 255
177. What all gets printed when the following gets compiled and run. Select all correct answers.
178.
179. public class example {
180. public static void main(String args[]) {
181. int x = 0;
182. if(x > 0) x = 1;
183.
184. switch(x) {
185. case 1: System.out.println(1);
186. case 0: System.out.println(0);
187. case 2: System.out.println(2);
188. break;
189. case 3: System.out.println(3);
190. default: System.out.println(4);
191. break;
192. }
193. }
194. }
195.
A. 0
B. 1
C. 2
D. 3
E. 4
196. What happens when the following class is compiled and run. Select one correct answer.
197.
198. public class test {
199. public static void main(String args[]) {
200. int x = 0, y = 1, z;
201. if(x)
202. z = 0;
203. else
204. z = 1;
205.
206. if(y)
207. z = 2;
208. else
209. z = 3;
210. System.out.println(z);
211. }
212. }
213.
A. The program prints 0
B. The program prints 1
C. The program prints 2
D. The program prints 3
E. The program does not compile because of problems in the if statement.
214. Which all lines are part of the output when the following code is compiled and run. Select all correct answers.
215.
216. public class test {
217. public static void main(String args[]) {
218. for(int i = 0; i = 0; j--) {
220. if(i == j) continue;
221. System.out.println(i + " " + j);
222. }
223. }
224. }
225. }
226.
A. 0 0
B. 0 1
C. 0 2
D. 0 3
E. 1 0
F. 1 1
G. 1 2
H. 1 3
I. 2 0
J. 2 1
K. 2 2
L. 2 3
M. 3 0
N. 3 1
O. 3 2
P. 3 3
Q. The program does not print anything.
227. Which all lines are part of the output when the following code is compiled and run. Select all correct answers.
228.
229. public class test {
230. public static void main(String args[]) {
231. for(int i = 0; i < 3; i++)
232. for(int j = 3; j <= 0; j--) {
233. if(i == j) continue;
234. System.out.println(i + " " + j);
235. }
236. }
237. }
238. }
239.
A. 0 0
B. 0 1
C. 0 2
D. 0 3
E. 1 0
F. 1 1
G. 1 2
H. 1 3
I. 2 0
J. 2 1
K. 2 2
L. 2 3
M. 3 0
N. 3 1
O. 3 2
P. 3 3
Q. The program does not print anything.
240. Which all lines are part of the output when the following code is compiled and run. Select all correct answers.
241.
242. public class test {
243. public static void main(String args[]) {
244. for(int i = 0; i = 0; j--) {
246. if(i == j) break;
247. System.out.println(i + " " + j);
248. }
249. }
250. }
251. }
252.
A. 0 0
B. 0 1
C. 0 2
D. 0 3
E. 1 0
F. 1 1
G. 1 2
H. 1 3
I. 2 0
J. 2 1
K. 2 2
L. 2 3
M. 3 0
N. 3 1
O. 3 2
P. 3 3
253. Which all lines are part of the output when the following code is compiled and run. Select all correct answers.
254.
255. public class test {
256. public static void main(String args[]) {
257. outer: for(int i = 0; i = 0; j--) {
259. if(i == j) continue outer;
260. System.out.println(i + " " + j);
261. }
262. }
263. }
264. }
265.
A. 0 0
B. 0 1
C. 0 2
D. 0 3
E. 1 0
F. 1 1
G. 1 2
H. 1 3
I. 2 0
J. 2 1
K. 2 2
L. 2 3
M. 3 0
N. 3 1
O. 3 2
P. 3 3
266. Which all lines are part of the output when the following code is compiled and run. Select all correct answers.
267.
268. public class test {
269. public static void main(String args[]) {
270. outer : for(int i = 0; i = 0; j--) {
272. if(i == j) break outer;
273. System.out.println(i + " " + j);
274. }
275. }
276. }
277. }
278.
A. 0 0
B. 0 1
C. 0 2
D. 0 3
E. 1 0
F. 1 1
G. 1 2
H. 1 3
I. 2 0
J. 2 1
K. 2 2
L. 2 3
M. 3 0
N. 3 1
O. 3 2
P. 3 3

________________________________________
Answers to questions on Operators and Asignments
17. c. It is not possible to assign an integer to a character in this case without a cast.
18. a, c, d, e. 2.3 is of type double. So it cannot be assigned to a float without a cast.
19. b
20. a, c, d, f. If RHS (Right hand side) is an integer within the correct range of LHS (Left hand side), and if LHS is char, byte, or short, no cast is required. A decimal number is a double by default. Assigning it to float requires a cast.
21. b
22. b. In the second assignment to variable b, the expression (i+=2) does not get evaluated.
23. d
24. c
25. d
26. a
27. h
28. c
29. f
30. b
31. a
32. d
33. d
34. f
35. d
36. b
37. a, c
38. e. The expression in the if statement must evaluate to a boolean.
39. b, c, d, e, g, h, i, j, l
40. q
41. b, c, d, g, h, l
42. b, c, d, g, h, l
43. b, c, d

Questions on Class Fundamentals
1. What gets displayed on the screen when the following program is compiled and run. Select the one correct answer.
2.
3. protected class example {
4. public static void main(String args[]) {
5. String test = "abc";
6. test = test + test;
7. System.out.println(test);
8. }
9. }
10.
A. The class does not compile because the top level class cannot be protected.
B. The program prints "abc"
C. The program prints "abcabc"
D. The program does not compile because statement "test = test + test" is illegal.
11. A top level class may have only the following access modifier. Select one correct answer.
A. package
B. friendly
C. private
D. protected
E. public
12. Write down the modifier of a method which makes the method available to all classes in the same package and to all the subclases of this class.
13. Select the one most appropriate answer. A top level class without any modifier is accessible to -
A. any class
B. any class within the same package
C. any class within the same file
D. any subclass of this class.
14. Is this True or False. In Java an abstract class cannot be subclassed.
15. Is this True or False. In Java a final class must be subclassed before it can be used.
16. Which of the following are true. Select all correct answers.
A. A static method may be invoked before even a single instance of the class is constructed.
B. A static method cannot access non-static methods of the class.
C. Abstract modifier can appear before a class or a method but not before a variable.
D. final modifier can appear before a class or a variable but not before a method.
E. Synchronized modifier may appear before a method or a variable but not before a class.
________________________________________
Answers to questions on classes in Java
1. a
2. e
3. protected
4. b
5. False
6. False
7. a, b, c. final modifier may appear before a method or a variable but not before a class.

Questions on Language Fundamentals
1. Which of these are legal identifiers. Select all the correct answers.
A. number_1
B. number_a
C. $1234
D. -volatile
2. Which of these are not legal identifiers. Select all the correct answers.
A. 1alpha
B. _abcd
C. xy+abc
D. transient
E. account-num
F. very_long_name
3. Which of the following are keywords in Java. Select all the correct answers.
A. friend
B. NULL
C. implement
D. synchronized
E. throws
4. Which of the following are Java keywords. Select all the correct answers.
A. super
B. strictfp
C. void
D. synchronize
E. instanceof
5. Which of these are Java keywords. Select all the correct answers
A. TRUE
B. volatile
C. transient
D. native
E. interface
F. then
G. new
6. Using up to four characters, write the Java representation of octal literal 6.
7. Using up to four characters, write the Java representation of integer literal 3 in hexadecimal.
8. Using up to four characters, write the Java representation of integer literal 10 in hexadecimal.
9. What is the minimum value of char type. Select the one correct answer.
A. 0
B. -215
C. -28
D. -215 - 1
E. -216
F. -216 - 1
10. How many bytes are used to represent the primitive data type int in Java. Select the one correct answer.
A. 2
B. 4
C. 8
D. 1
E. The number of bytes to represent an int is compiler dependent.
11. What is the legal range of values for a variable declared as a byte. Select the one correct answer.
A. 0 to 256
B. 0 to 255
C. -128 to 127
D. -128 to 128
E. -127 to 128
F. -215 to 215 - 1
12. The width in bits of double primitive type in Java is --. Select the one correct answer.
A. The width of double is platform dependent
B. 64
C. 128
D. 8
E. 4
13. What would happen when the following is compiled and executed. Select the one correct answer.
14.
15. public class Compare {
16. public static void main(String args[]) {
17. int x = 10, y;
18. if(x = 10) y = 2;
21. System.out.println("y is " + y);
22. }
23. }
24.
A. The program compiles and prints y is 0 when executed.
B. The program compiles and prints y is 1 when executed.
C. The program compiles and prints y is 2 when executed.
D. The program does not compile complaining about y not being initialized.
E. The program throws a runtime exception.
25. What would happen when the following is compiled and executed. Select the one correct answer.
26.
27. class example {
28. int x;
29. int y;
30. String name;
31. public static void main(String args[]) {
32. example pnt = new example();
33. System.out.println("pnt is " + pnt.name +
34. " " + pnt.x + " " + pnt.y);
35. }
36. }
37.
A. The program does not compile because x, y and name are not initialized.
B. The program throws a runtime exception as x, y, and name are used before initialization.
C. The program prints pnt is 0 0.
D. The program prints pnt is null 0 0.
E. The program prints pnt is NULL false false
38. The initial value of an instance variable of type String which is not explicitly initialized in the program is --. Select the one correct answer.
A. null
B. ""
C. NULL
D. 0
E. The instance variable must be explicitly assigned.
39. The initial value of a local variable of type String which is not explicitly initialized and which is defined in a member function of a class. Select all the correct answer.
A. null
B. ""
C. NULL
D. 0
E. The local variable must be explicitly assigned.
40. Which of the following are legal Java programs. Select all the correct answer.
A. // The comments come before the package
package pkg;
import java.awt.*;
class C{};
B. package pkg;
import java.awt.*;
class C{};
C. package pkg1;
package pkg2;
import java.awt.*;
class C{};
D. package pkg;
import java.awt.*;
E. import java.awt.*;
class C{};
F. import java.awt.*;
package pkg;
class C {};
41. Which of the following statements are correct. Select all correct answers.
A. A Java program must have a package statement.
B. A package statement if present must be the first statement of the program
C. If a Java program defines both a package and import statement, then the import statement must come before the package statement.
D. An empty file is a valid source file.
E. A Java file without any class or interface definitions can also be compiled.
F. If an import statement is present, it must appear before any class or interface definitions.
42. What would be the results of compiling and running the following class. Select the one correct answer.
43.
44. class test {
45. public static void main() {
46. System.out.println("test");
47. }
48. }
49.
A. The program does not compile as there is no main method defined.
B. The program compiles and runs generating an output of "test"
C. The program compiles and runs but does not generate any output.
D. The program compiles but does not run.
50. Which of these are valid declarations for the main method? Select all correct answers.
A. public void main();
B. static void main(String args[]);
C. public static void main(String args[]);
D. static public void main(String);
E. public static void main(String );
F. public static int main(String args[]);
51. Which of the following are valid declarations for the main method. Select all correct answers.
A. public static void main(String args[]);
B. public static void main(String []args);
C. final static public void main (String args[]);
D. public static int main(String args[]);
E. public static abstract void main(String args[]);
52. What happens when the following program is compiled and executed with the arguments - java test. Select the one correct answer.
53.
54. class test {
55. public static void main(String args[]) {
56. if(args.length > 0)
57. System.out.println(args.length);
58. }
59. }
60.
A. The program compiles and runs but does not print anything.
B. The program compiles and runs and prints 0
C. The program compiles and runs and prints 1
D. The program compiles and runs and prints 2
E. The program does not compile.
61. What is the result of compiling and running this program ? Select the one correct answer.
62.
63. public class test {
64. public static void main(String args[]) {
65. int i, j;
66. int k = 0;
67. j = 2;
68. k = j = i = 1;
69. System.out.println(k);
70. }
71. }
72.
73.
A. The program does not compile as k is being read without being initialized.
B. The program does not compile because of the statement k = j = i = 1;
C. The program compiles and runs printing 0.
D. The program compiles and runs printing 1.
E. The program compiles and runs printing 2.
74. What gets printed on the standard output when the class below is compiled and executed by entering "java test lets see what happens". Select the one correct answer.
75.
76. public class test {
77. public static void main(String args[]) {
78. System.out.println(args[0] + " " + args[args.length - 1]);
79. }
80. }
81.
A. The program will throw an ArrayIndexOutOfBounds exception.
B. The program will print "java test"
C. The program will print "java hapens";
D. The program will print "test happens"
E. The program will print "lets happens"
82. What gets printed on the standard output when the class below is compiled and executed by entering "java test lets see what happens". Select the one correct answer.
83.
84. public class test {
85. public static void main(String args[]) {
86. System.out.println(args[0] + " " + args[args.length]);
87. }
88. }
89.
A. The program will throw an ArrayIndexOutOfBounds exception.
B. The program will print "java test"
C. The program will print "java hapens";
D. The program will print "test happens"
E. The program will print "lets happens"
90. What all gets printed on the standard output when the class below is compiled and executed by entering "java test lets see what happens". Select all correct answers.
91.
92. public class test {
93. public static void main(String args[]) {
94. System.out.println(args[0] + " " + args.length);
95. }
96. }
97.
A. java
B. test
C. lets
D. 3
E. 4
F. 5
G. 6
98. What happens when the following program is compiled and run. Select the one correct answer.
99.
100. public class example {
101. int i = 0;
102. public static void main(String args[]) {
103. int i = 1;
104. i = change_i(i);
105. System.out.println(i);
106. }
107. public static int change_i(int i) {
108. i = 2;
109. i *= 2;
110. return i;
111. }
112. }
113.
A. The program does not compile.
B. The program prints 0.
C. The program prints 1.
D. The program prints 2.
E. The program prints 4.
114. What happens when the following program is compiled and run. Select the one correct answer.
115.
116. public class example {
117. int i = 0;
118. public static void main(String args[]) {
119. int i = 1;
120. change_i(i);
121. System.out.println(i);
122. }
123. public static void change_i(int i) {
124. i = 2;
125. i *= 2;
126. }
127. }
128.
A. The program does not compile.
B. The program prints 0.
C. The program prints 1.
D. The program prints 2.
E. The program prints 4.
129. What happens when the following program is compiled and run. Select the one correct answer.
130.
131. public class example {
132. int i[] = {0};
133. public static void main(String args[]) {
134. int i[] = {1};
135. change_i(i);
136. System.out.println(i[0]);
137. }
138. public static void change_i(int i[]) {
139. i[0] = 2;
140. i[0] *= 2;
141. }
142. }
143.
A. The program does not compile.
B. The program prints 0.
C. The program prints 1.
D. The program prints 2.
E. The program prints 4.
144. What happens when the following program is compiled and run. Select the one correct answer.
145.
146. public class example {
147. int i[] = {0};
148. public static void main(String args[]) {
149. int i[] = {1};
150. change_i(i);
151. System.out.println(i[0]);
152. }
153. public static void change_i(int i[]) {
154. int j[] = {2};
155. i = j;
156. }
157. }
158.
A. The program does not compile.
B. The program prints 0.
C. The program prints 1.
D. The program prints 2.
E. The program prints 4.

________________________________________
Answers to questions on Language Fundamentals
6. a, b, c
7. a, c, d, e
8. d, e
9. a, b, c, e
10. b, c, d, e, g
11. Any of the following are correct answers - 06, 006, or 0006
12. Any of the following are correct answers - 0x03, 0X03, 0X3 or 0x3
13. Any of the following are correct answers - 0x0a, 0X0a, 0Xa, 0xa, 0x0A, 0X0A, 0XA, 0xA
14. a
15. b
16. c
17. b
18. d. The variable y is getting read before being properly initialized.
19. d. Instance variable of type int and String are initialized to 0 and NULL respectively.
20. a
21. e
22. a, b, d, e
23. b, d, e, f
24. d
25. b, c
26. a, b, c
27. a
28. d
29. e
30. a
31. c, e
32. e
33. c
34. e
35. c
Questions on Collections
1. TreeMap class is used to implement which collection interface. Select the one correct answer.
A. Set
B. SortedSet
C. List
D. Map
E. SortedMap
2. Name the Collection interface implemented by the Vector class.
3. Name the Collection interface implemented by the HashTable class.
4. Name the Collection interface implemented by the HashSet class.
5. Which of these are interfaces in the collection framework. Select all correct answers.
A. Set
B. List
C. Array
D. Vector
E. LinkedList
6. Which of these are interfaces in the collection framework. Select all correct answers.
A. HashMap
B. ArrayList
C. Collection
D. SortedMap
E. TreeMap
7. What is the name of collection interface used to maintain non-unique elements in order.
8. What is the name of collection interface used to maintain unique elements.
9. What is the name of collection interface used to maintain mappings pf keys to values.
10. Is this true or false. Map interface is derived from the Collection interface.
A. True
B. False
________________________________________
Answers to questions on Layout Managers
1. e
2. List
3. Map
4. Set
5. a,b
6. c,d
7. List
8. Set
9. Map
10. b

Questions on Events
1. Name the method defined in EventObject class that returns the Object generated from the event. Select the one correct answer.
A. getEvent()
B. getObject()
C. getID()
D. getSource()
2. What is the return type of the method getID() defined in AWTEvent class. Select the one correct answer.
A. int
B. long
C. Object
D. Component
E. short
3. Name the event which gets generated when a button is clicked. Select the one correct answer.
A. KeyEvent
B. MouseEvent
C. ItemEvent
D. ActionEvent
4. Which event is generated when the position of a scrollbar is changed. Select the one correct answer.
A. KeyEvent
B. MouseEvent
C. ItemEvent
D. ActionEvent
E. AdjustmentEvent
5. Which of the following Objects can generate ActionEvent. Select all correct answer.
A. List
B. TextArea
C. CheckBoxMenuItem
D. Choice
6. Which of the following Objects can generate ItemEvent. Select all correct answer.
A. CheckBox
B. Button
C. List
D. MenuItem
7. Which method identifies the type of an event generated. Select the one correct answer.
A. getSource()
B. getType()
C. getEventType()
D. getID()
8. Which of the following are legal adapter classes in Java. Select all correct answers.
A. ActionAdapter
B. ItemAdapter
C. TextAdapter
D. MouseAdapter
E. MouseMotionAdapter
9. Name the class of the argument of method actionPerformed() defined in the ActionListner interface.
10. Which of these listner classes have corresponding adapter classes. Select all correct answers.
A. ContainerListner
B. TextListner
C. ItemListner
D. MouseMotionListner
11. Which of these are valid adapter classes. Select all correct answers.
A. ActionAdapter
B. AdjustmentAdapter
C. KeyAdapter
D. TextAdapter
12. Which of these methods are defined in MouseMotionListner interface. Select all correct answers.
A. mouseClicked()
B. mousePressed()
C. mouseEntered()
D. mouseDragged()
E. mouseMoved()
13. What is the return type of the method getSource() defined in EventObject class. Select the one correct answer.
A. int
B. long
C. Object
D. Component
E. short
________________________________________
Answers to questions on Events
1. d
2. a
3. d
4. e
5. a
6. a, c
7. d
8. d, e
9. ActionEvent
10. a, d
11. c
12. d, e
13. c

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