Musings…

Gideon, a member of our 4 yr old PinoyJUG mailing list used javap to see if there was a difference in the bytecodes.

Quoting his test:

It seems that javac generates the same byte code for both these
implementation of endless loops.

–begin While.java–
public class While {

public static void main() {
while (true) {
}
}

}
–end While.java–

output of “javap -c While.java”
–begin–
public class While extends java.lang.Object{
public While();
Code:
0: aload_0
1: invokespecial #1; //Method java/lang/Object.”":()V
4: return

public static void main();
Code:
0: goto 0

}
–end–

–begin ForLoop.java–
public class ForLoop {

public static void main() {
for(;;);
}

}
–end ForLoop.java–

output of “javap -c ForLoop.java”
–begin–
public class ForLoop extends java.lang.Object{
public ForLoop();
Code:
0: aload_0
1: invokespecial #1; //Method java/lang/Object.”":()V
4: return

public static void main();
Code:
0: goto 0

}
–end–

According to his test there isn’t any difference in the bytecode generated. Well there’s this guy who is debating that there is a difference in terms of faster processing of the controversial contructs. Is there really a difference? Maybe someone from Sun can enlighten us regarding this matter.

So whatchathink? Which is faster?