单项选择题

class A {  
public int getNumber(int a) {  
return a + 1;  
}  
}  
 class B extends A {  
public int getNumber (int a) {  
return a + 2  
}  
 public static void main (String args) {  
A a = new B();  
System.out.printIn(a.getNumber(0));  
}  
}  
What is the result? () 

A. Compilation succeeds and 1 is printed.
B. Compilation succeeds and 2 is printed.
C. An error at line 8 causes compilation to fail.
D. An error at line 13 causes compilation to fail.
E. An error at line 14 causes compilation to fail.


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1.单项选择题

import java.awt.*;  
public class Test extends Frame {  
public Test() {  
add(new Label(“Hello”) );  
add(new TextField(“Hello”) );  
add(new Button(“Hello”) );  
pack();  
show();  
 }  
public static void main(String args) {  
new Test ();  
}  
}  
What is the result? () 

A. The code will not compile.
B. A Window will appear containing only a Button.
C. An IllegalArgumentException is thrown at line 6.
D. A Window button will appear but will not contain the Label, TextField, or Button.
E. A Window will appear containing a Label at the top, a TextField below the Label, and a Button  below the TextField.
F. A Window will appear containing a Label on the left, a TextField to the right of the Label, and a button to the right of the TextField.

2.单项选择题Given an ActionEvent, which method allows you to identify the affected Component?()  

A. Public class getClass()
B. Public Object getSource()
C. Public Component getSource()
D. Public Component getTarget()
E. Public Component getComponent()
F. Public Component getTargetComponent()

3.单项选择题Which statement is true?()  

A. A flow layout can be used to position a component that should resize horizontally when the  container is resized.
B. A grid layout can be used to position a component tat should maintain a constant size even when  the container is resized.
C. A border layout can be used to position component that should maintain a constant size even when  the container is resized.
D. The grid bag layout can be used to give a grid-like layout which differs from the normal grid in that individual rows and columns can have unique sizes.
E. If two components are placed in the same column of a grid bag layout, and one component resizes horizontally, then the other component must resize horizontally.

4.单项选择题Which code determines the int value foo closest to, but not greater than, a double value bar?()  

A. Int foo = (int) Math.max(bar);
B. Int foo = (int) Math.min(bar);
C. Int foo = (int) Math.abs(bar);
D. Int foo = (int) Math.ceil(bar);
E. Int foo = (int) Math.floor(bar);
F. Int foo = (int) Math.round(bar);

6.单项选择题Which method in the Thread class is used to create and launch a new thread of execution?()

A. Run();
B. Start();
C. Execute();
D. Run(Runnable r);
E. Start(Runnable r);
F. Execute(Thread t);

8.多项选择题Which two CANNOT directly cause a thread to stop executing? ()  

A. Existing from a synchronized block.
B. Calling the wait method on an object.
C. Calling notify method on an object.
D. Calling read method on an InputStream object.
E. Calling the SetPriority method on a Thread object.

9.单项选择题

public class X implements Runnable (  
private int x;  
private int y;  
 public static void main(String args) (  
X that = new X();  
(new Thread(that)) . start( ); 
 (new Thread(that)) . start( );  
)  
 public synchronized void run( ) (  
 for (;;) (  
 x++;  
 y++;  
 System.out.printIn(“x = “ + x + “, y = “ + y);  
 ) 
 )  
 )  
What is the result?()

A. An error at line 11 causes compilation to fail.
B. Errors at lines 7 and 8 cause compilation to fail.
C. The program prints pairs of values for x and y that might not always be the same on the same line  (for example, “x=2, y=1”)
D. The program prints pairs of values for x and y that are always the same on the same line (forexample, “x=1, y=1”. In addition, each value appears twice (for example, “x=1, y=1” followed by  “x=1, y=1”)
E. The program prints pairs of values for x and y that are always the same on the same line (for example, “x=1, y=1”. In addition, each value appears twice (for example, “x=1, y=1” followed by  “x=2s, y=2”)