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Axl · Guest

Ok, I don't get this. I'm using the mock test from Sun and here's the
question:

Given:

1. public static void main( String[] args ) {
2. class T1 extends java.lang.Thread{}
3. class T2 extends T1{}
4. class T3 implements java.lang.Runnable{}
5.
6. new T1().start();
7. new T2().start();
8. new Thread(new T3()).start();
9. System.out.println( "Executing" );
10. }

Here's the multiple choice answers:

A - Compilation fails.
B - The program never terminates.
C - The program runs with no output.
D - An exception is thrown at runtime.
E - The program outputs Executing and then terminates.
F - The program terminates after the third thread is created.

The correct answer according to the test reference is:
Option A. Compilation failure, T3 does not implement the interface Runnable
and is therefore abstract and cannot be instantiated

I don't understand that answer. Doesn't T3 implement the Runnable interface
in line 4??? Where am I going wrong with my reasoning?

Thanks,
Axl

Peter Kirk · Guest

"Axl" <axlstowe (AT) nospamhere (DOT) com> skrev i en meddelelse
news:108flrclt497d4b (AT) corp (DOT) supernews.com...
<snip>

Doug Schwartz · Guest

Runnable has one method, run (the signature is "void run()"). Since T3 did
not implement run, the class cannot compile.

doug

"Peter Kirk" <peter> wrote

xaos · Guest

T3 does not define the method "public void run(){}" as required by the
Runnable interface.

Line 8, for instance, depends on that run method -which is missing.

~S~

Axl wrote: