Name: diC59631 Date: 06/18/98


It seems impossible to do a normal step-over by line when in a static initializer. The VM always behaves as if you're doing a step-into by byte code.

I created a jdb testcase that shows the problem. I compiled
these two simple Java classes (with -g) and then did a jdb session, a log
of which I also included in this email.

Note that the jdb command 'step' means "step into, step by line number",
and "next" means "step over, step by line number". OK. You can see the
problem by looking at the log when I enter MyOtherClass.<clinit> (the
static initializer). You'll see that I keep entering "next" but that it is
stepping per byte code and then it steps into foo(), when it should be
stepping by line number and stepping over the foo call.

This is exactly the same behavior that is happening in my CodeWarrior
debugger plugin. It is very annoying.

I wonder if this doesn't have something to do with the class lock that
occurs when inside a static initializer (the reason why you can't do a
source listing or class dump while you're in a static initializer). I've
seen this in another bug report and I wonder if that is the reason why the
VM must do a step by bytecode when in the clinit.

John

Let me know if you have any questions.

MyClass.java
--------------
public class MyClass
{
        public static void main(String args[])
        {
                int i = MyOtherClass.s1;
                MyOtherClass.s1 = 300;
                MyOtherClass.s2 = MyOtherClass.foo();
        }
}

MyOtherClass.java
--------------
public class MyOtherClass
{
        public static int s1 = 100;
        public static int s2 = foo();

        static int foo()
        {
                return 500;
        }
}

C:\TEMP>jdb MyClass
Initializing jdb...
Warning: JIT compiler "symcjit" not found. Will use interpreter.
0xf981f0:class(MyClass)
> stop in MyClass.main
Breakpoint set in MyClass.main
> run
run MyClass
running ...
main[1]
Breakpoint hit: MyClass.main (MyClass:5)
main[1] list
1 public class MyClass
2 {
3 public static void main(String args[])
4 {
5 => int i = MyOtherClass.s1;
6 MyOtherClass.s1 = 300;
7 MyOtherClass.s2 = MyOtherClass.foo();
8 }
9 }
main[1] step
main[1]
Breakpoint hit: MyOtherClass.<clinit> (MyOtherClass:3)
main[1] next
main[1]
Breakpoint hit: MyOtherClass.<clinit> (MyOtherClass:3)
main[1] next
main[1]
Breakpoint hit: MyOtherClass.<clinit> (MyOtherClass:3)
main[1] next
main[1]
Breakpoint hit: MyOtherClass.<clinit> (MyOtherClass:4)
main[1] next

Breakpoint hit: MyOtherClass.<clinit> (MyOtherClass:4)
main[1] main[1] next
main[1]
Breakpoint hit: MyOtherClass.foo (MyOtherClass:8)
main[1] next
main[1]
Breakpoint hit: MyOtherClass.<clinit> (MyOtherClass:4)
main[1] next
main[1]
Breakpoint hit: MyOtherClass.<clinit> (MyOtherClass:4)
main[1] next
main[1]
Breakpoint hit: MyOtherClass.<clinit> (MyOtherClass:1)
main[1] next

Breakpoint hit: MyClass.main (MyClass:5)
main[1] main[1] next
main[1]
Breakpoint hit: MyClass.main (MyClass:6)
main[1] next
main[1]
Breakpoint hit: MyClass.main (MyClass:7)
main[1] next
main[1]
Breakpoint hit: MyClass.main (MyClass:3)
main[1]


(Review ID: 33675)
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