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What will happen when you
attempt to compile and run this code?
abstract class Base{
abstract public void myfunc();
public void another(){
System.out.println("Another method");
}
}
public class Abs extends Base{
public static void main(String argv[]){
Abs a = new Abs();
a.amethod();
}
public void myfunc(){
System.out.println("My func");
}
public void amethod(){
myfunc();
}
}
1) The code will compile and run,
printing out the words "My Func"
2) The compiler will complain that the Base class has non abstract methods
3) The code will compile but complain at run time that the Base class has non
abstract methods
4) The compiler will complain that the method myfunc
in the base class has no body, nobody at all to looove
it
Question 2)
What will happen when you attempt to compile and run this code?
public class MyMain{
public static void main(String argv){
System.out.println("Hello cruel world");
}
}
1) The compiler will complain that
main is a reserved word and cannot be used for a class
2) The code will compile and when run will print out "Hello cruel
world"
3) The code will compile but will complain at run time that no constructor is
defined
4) The code will compile but will complain at run time that main is not
correctly defined
Which of the following are
Java modifiers?
1)public
2) private
3) friendly
4) transient
4) vagrant
What will happen when you
attempt to compile and run this code?
class Base{
abstract public void myfunc();
public void another(){
System.out.println("Another method");
}
}
public class Abs extends Base{
public static void main(String argv[]){
Abs a = new Abs();
a.amethod();
}
public void myfunc(){
System.out.println("My func");
}
public void amethod(){
myfunc();
}
}
1) The code will compile and run,
printing out the words "My Func"
2) The compiler will complain that the Base class is not declared as abstract.
3) The code will compile but complain at run time that the Base class has non
abstract methods
4) The compiler will complain that the method myfunc
in the base class has no body, nobody at all to looove
it
Why might you define a
method as native?
1) To get to access hardware that
Java does not know about
2) To define a new data type such as an unsigned integer
3) To write optimised code for performance in a
language such as C/C++
4) To overcome the limitation of the private scope of a method
What will happen when you
attempt to compile and run this code?
class Base{
public final void amethod(){
System.out.println("amethod");
}
}
public class Fin extends Base{
public static void main(String argv[]){
Base b = new Base();
b.amethod();
}
}
1) Compile time error indicating
that a class with any final methods must be declared final itself
2) Compile time error indicating that you cannot inherit from a class with
final methods
3) Run time error indicating that Base is not defined as final
4) Success in compilation and output of "amethod"
at run time.
What will happen when you
attempt to compile and run this code?
public class Mod{
public static void main(String argv[]){
}
public static native void amethod();
}
1) Error at compilation: native
method cannot be static
2) Error at compilation native method must return value
3) Compilation but error at run time unless you have made code containing
native amethod available
4) Compilation and execution without error
What will happen when you
attempt to compile and run this code?
private class Base{}
public class
transient int iVal;
public static void main(String elephant[]){
}
}
1)Compile time error: Base cannot be
private
2)Compile time error indicating that an integer cannot be transient
3)Compile time error transient not a data type
4)Compile time error malformed main method
What happens when you
attempt to compile and run these two files in the same directory?
//File P1.java
package MyPackage;
class P1{
void afancymethod(){
System.out.println("What a fancy method");
}
}
//File P2.java
public class P2 extends P1{
afancymethod();
}
1) Both compile and P2 outputs
"What a fancy method" when run
2) Neither will compile
3) Both compile but P2 has an error at run time
4) P1 compiles cleanly but P2 has an error at compile time
You want to find out the
value of the last element of an array. You write the following code. What will
happen when you compile and run it.?
public class MyAr{
public static void main(String argv[]){
int[] i = new int[5];
System.out.println(i[5]);
}
}
1) An error at compile time
2) An error at run time
3) The value 0 will be output
4) The string "null" will be output
You want to loop through
an array and stop when you come to the last element. Being a good java
programmer and forgetting everything you ever knew about C/C++ you know that
arrays contain information about their size. Which of the following can you
use?
1)myarray.length();
2)myarray.length;
3)myarray.size
4)myarray.size();
What best describes the
appearance of an applet with the following code?
import java.awt.*;
public class FlowAp
extends Frame{
public static void main(String argv[]){
FlowAp fa=new FlowAp();
fa.setSize(400,300);
fa.setVisible(true);
}
FlowAp(){
add(new Button("One"));
add(new Button("Two"));
add(new Button("Three"));
add(new Button("Four"));
}//End of constructor
}//End of Application
1) A Frame with buttons marked One
to Four placed on each edge.
2) A Frame with buutons marked One to four running
from the top to bottom
3) A Frame with one large button marked Four in the Centre
4) An Error at run time indicating you have not set a LayoutManager
How do you indicate where
a component will be positioned using Flowlayout?
1) North, South,East,West
2) Assign a row/column grid reference
3) Pass a X/Y percentage parameter to the add method
4) Do nothing, the FlowLayout will position the
component
How do you change the
current layout manager for a container
1) Use the setLayout
method
2) Once created you cannot change the current layout
manager of a component
3) Use the setLayoutManager method
4) Use the updateLayout method
Which of the following are
fields of the GridBagConstraints class?
1) ipadx
2) fill
3) insets
4) width
What most closely matches
the appearance when this code runs?
import java.awt.*;
public class CompLay
extends Frame{
public static void main(String argv[]){
CompLay cl = new CompLay();
}
CompLay(){
Panel p = new Panel();
p.setBackground(Color.pink);
p.add(new
Button("One"));
p.add(new
Button("Two"));
p.add(new
Button("Three"));
add("South",p);
setLayout(new
FlowLayout());
setSize(300,300);
setVisible(true);
}
}
1) The buttons will run from left to
right along the bottom of the Frame
2) The buttons will run from left to right along the top of the frame
3) The buttons will not be displayed
4) Only button three will show occupying all of the frame
Which statements are
correct about the anchor field?
1) It is a field of the GridBagLayout manager for controlling component placement
2) It is a field of the GridBagConstraints
class for controlling component placement
3) A valid setting for the anchor field is GridBagConstraints.NORTH
4) The anchor field controls the height of components added to a container
What will happen when you
attempt to compile and run the following code?
public class Bground
extends Thread{
public static void main(String argv[]){
Bground b =
new Bground();
b.run();
}
public void start(){
for (int i = 0; i
<10; i++){
System.out.println("Value
of i = " + i);
}
}
}
1) A compile time error indicating
that no run method is defined for the Thread class
2) A run time error indicating that no run method is defined for the Thread
class
3) Clean compile and at run time the values 0 to 9 are printed out
4) Clean compile but no output at runtime
When using the GridBagLayout manager, each new component requires a new
instance of the GridBagConstraints class. Is this
statement
1) true
2) false
Which most closely matches
a description of a Java Map?
1) A vector of arrays for a 2D
geographic representation
2) A class for containing unique array elements
3) A class for containing unique vector elements
4) An interface that ensures that implementing classes cannot contain
duplicates
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
exit(0);
2) The priority of another thread is increased
3) A call to the stop method of the Thread class
4) A call to the halt method of the Thread class
For a class defined insid