How does the set collection deal with duplicate elements?
1) An exception is thrown if you attempt to add an element with a duplicate
value
2) The add method returns false if you attempt to add an element
with a duplicate value
3) A set may contain elements that return duplicate
values from a call to the equals method
4) Duplicate values will cause an
error at compile time
What can cause a thread to stop executing?
1) The program exits via a call to System.exit(0);
2) Another thread is
given a higher priority
3) A call to the thread's stop method.
4) A call
to the halt method of the Thread class
For a class defined inside a method, what rule governs access to the variables of the enclosing method?
1) The class can access any variable
2) The class can only access static
variables
3) The class can only access transient variables
4) The class
can only access final variables
Under what circumstances might you use the yield method of the Thread
class
1) To call from the currently running thread to allow another thread of the
same or higher priority to run
2) To call on a waiting thread to allow it to
run
3) To allow a thread of higher priority to run
4) To call from the
currently running thread with a parameter designating which thread should be
allowed to run
What will happen when you attempt to compile and run the following code
public class Hope{
public static void main(String argv[]){
Hope h = new Hope();
}
protected Hope(){
for(int i =0; i <10; i ++){
System.out.println(i);
}
}
}
1) Compilation error: Constructors cannot be declared protected
2) Run
time error: Constructors cannot be declared protected
3) Compilation and
running with output 0 to 10
4) Compilation and running with output 0 to 9
What will happen when you attempt to compile and run the following code
public class MySwitch{
public static void main(String argv[]){
MySwitch ms= new MySwitch();
ms.amethod();
}
public void amethod(){
int k=10;
switch(k){
default: //Put the default at the bottom, not here
System.out.println("This is the default output");
break;
case 10:
System.out.println("ten");
case 20:
System.out.println("twenty");
break;
}
}
}
1) None of these options
2) Compile time error target of switch must be an
integral type
3) Compile and run with output "This is the default
output"
4) Compile and run with output of the single line "ten"
Which of the following is the correct syntax for suggesting that the JVM performs garbage collection
1) System.free();
2) System.setGarbageCollection();
3)
System.out.gc();
4) System.gc();
What will happen when you attempt to compile and run the following
code
public class As{
int i = 10;
int j;
char z= 1;
boolean b;
public static void main(String argv[]){
As a = new As();
a.amethod();
}
public void amethod(){
System.out.println(j);
System.out.println(b);
}
}
1) Compilation succeeds and at run time an output of 0 and false
2)
Compilation succeeds and at run time an output of 0 and true
3) Compile time
error b is not initialised
4) Compile time error z must be assigned a char
value
What will happen when you attempt to compile and run the following code
with the command line "hello there"
public class Arg{
String[] MyArg;
public static void main(String argv[]){
MyArg=argv;
}
public void amethod(){
System.out.println(argv[1]);
}
}
1) Compile time error
2) Compilation and output of "hello"
3)
Compilation and output of "there"
4) None of the above
What will happen when you attempt to compile and run the following code
public class StrEq{
public static void main(String argv[]){
StrEq s = new StrEq();
}
private StrEq(){
String s = "Marcus";
String s2 = new String("Marcus");
if(s == s2){
System.out.println("we have a match");
}else{
System.out.println("Not equal");
}
}
}
1) Compile time error caused by private constructor
2) Output of "we have
a match"
3) Output of "Not equal"
4) Compile time error by attempting to
compare strings using ==
1) What will happen when you attempt to compile and run the following code
import java.io.*;
class Base{
public static void amethod()throws FileNotFoundException{}
}
public class ExcepDemo extends Base{
public static void main(String argv[]){
ExcepDemo e = new ExcepDemo();
}
public static void amethod(){}
protected ExcepDemo(){
try{
DataInputStream din = new DataInputStream(System.in);
System.out.println("Pausing");
din.readChar();
System.out.println("Continuing");
this.amethod();
}catch(IOException ioe) {}
}
}
1)Compile time error caused by protected constructor
2) Compile time error
caused by amethod not declaring Exception
3) Runtime error caused by
amethod not declaring Exception
4) Compile and run with output of "Pausing"
and "Continuing" after a key is hit
What will happen when you attempt to compile and run this program
public class Outer{
public String name = "Outer";
public static void main(String argv[]){
Inner i = new Inner();
i.showName();
}//End of main
private class Inner{
String name =new String("Inner");
void showName(){
System.out.println(name);
}
}//End of Inner class
}
1) Compile and run with output of "Outer"
2) Compile and run with output
of "Inner"
3) Compile time error because Inner is declared as private
4)
Compile time error because of the line creating the instance of Inner
What will happen when you attempt to compile and run this code
//Demonstration of event handling
import java.awt.event.*;
import java.awt.*;
public class MyWc extends Frame implements WindowListener{
public static void main(String argv[]){
MyWc mwc = new MyWc();
}
public void windowClosing(WindowEvent we){
System.exit(0);
}//End of windowClosing
public void MyWc(){
setSize(300,300);
setVisible(true);
}
}//End of class
1) Error at compile time
2) Visible Frame created that that can be
closed
3) Compilation but no output at run time
4) Error at compile time
because of comment before import statements
Which option most fully describes will happen when you attempt to compile and run the following code
public class MyAr{
public static void main(String argv[]) {
MyAr m = new MyAr();
m.amethod();
}
public void amethod(){
static int i;
System.out.println(i);
}
}
1) Compilation and output of the value 0
2) Compile time error because i
has not been initialized
3) Compilation and output of null
4) Compile time
error
Which of the following will compile correctly
1) short myshort = 99S;
2) String name = 'Excellent tutorial Mr
Green';
3) char c = 17c;
4)int z = 015;
Which of the following are Java key
words
1)double
2)Switch
3)then
4)instanceof
What will be output by the following line?
System.out.println(Math.floor(-2.1));
1) -2
2) 2.0
3) -3
4) -3.0
Given the following main method in a class called Cycle and a command line of
java Cycle one two
what will be output?
public static void main(String bicycle[]){
System.out.println(bicycle[0]);
}
1) None of these options
2) cycle
3) one
4) two
Which of the following statements are true?
1) At the root of the collection hierarchy is a class called Collection
2)
The collection interface contains a method called enumerator
3) The interator
method returns an instance of the Vector class
4) The set interface is
designed for unique elements
Which of the following statements are correct?
1) If multiple listeners are added to a component only events for the last
listener added will be processed
2) If multiple listeners are added to a
component the events will be processed for all but with no guarantee in the
order
3) Adding multiple listeners to a comnponent will cause a compile time
error
4) You may remove as well add listeners to a component.