General Java Questions I

I hope the next versions of Java explores this issue.

Answer: It does. They re called interfaces:

interface A { public void setX(); public void setY(); public void setAll(); }

interface B { public void setC(); public void setD(); public void setBoth(); }

interface C extends A,B {};

public abstract class D implements C {

}

jim

 Is there a way to know from class X which class called the method foo()?

If class A and class B are calling a method foo() on class X, is there a way to know

from class X which class called the method foo() (they can be either A or B). I know

that this can be done by capturing the stack trace and examining it, but that solution

looks expensive as I have to create a new Throwable object every time and capture

stack trace (And I do this quite frequently).

Is there any other elegant solution to do this, any help and direction

is appreciated.

Answer: Pass a reference to the class to the foo() method.

foo(Object x){

      System.out.println(x.getClass());

}

should do it.

Why does this simple application never exit?

public class UIQuitTest {

    public static void main (String[] args) {

       java.awt.Frame f = new java.awt.Frame();

       f.dispose();

       f = null;

   } // end of main ()

}

The application above never quits, is it a bug or a (mis)feature? Win98, JRE 1.3.0

Answer: By creating an AWT object, you now have started the AWT thread. In order

to end the application now, you have to do a System.exit(0) that will kill all

non daemon threads, including the AWT thread.

 Q: Is it possible to stop an object from being created during construction?

For example if an error occurs inside the constructor (e.g. the parameters pass in

were invalid) and I wanted to stop an object being created would it be possible to

return null rather than a reference to a new object. (I know the term return is

technically correct in this case but you know what I mean).

Basically, is it possible to cancel object creation?

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