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From Gregory Shimansky <gshiman...@gmail.com>
Subject Re: [M3] NPE is thrown while debugging with M3
Date Wed, 10 Oct 2007 11:39:05 GMT
Andrew Zhang wrote:
> On 10/10/07, Tim Ellison <t.p.ellison@gmail.com> wrote:
>> Gregory Shimansky wrote:
>>> Andrew Zhang wrote:
>>>> Hi all,
>>>>
>>>> I meet a problem when debugging java application with M3. It throws NPE
>>>> immediately after pressing F5/F6. Here's simple test:
>>>>
>>>> public static void main(String[] args) {
>>>>         int count = 100;
>>>>         for(int i = 0; i < count; ++i) {
>>>>             System.out.println(i); // put a breakpoint here.
>>>>         }
>>>>     }
>>>>
>>>> It looks like a serious bug. It's reproducible here, with Eclipse 3.2.2
>> .
>>>> Thanks!
>>> I tried both M3 JDK snapshot for libstdc++.so.6 and current local debug
>>> development build of harmony, I couldn't reproduce this. Could you
>>> please give more details which platform you are using and how you are
>>> running this test? How does NPE stack trace look like?
> 
> 
> Hi,
> 
> Here are some more details:
> 
> NPE stack trace:
> 
> Thread [main] (Suspended)
>     NullPointerException.<init>() line: 34
>     AbstractInterruptibleChannel.<clinit>() line: 57 [local variables
> unavailable]

Hmm. This isn't exactly what I wanted to see. I just wanted to see the 
NPE stack trace that a program would print out when it throws an 
uncaught NPE in main(). It is quite strange for me to see that you've 
somehow stepped into AbstractInterruptibleChannel. There is no main() 
function on the bottom of the stack either...

I tried debugging on windows with M3 build and current development debug 
build and still I don't get any NPEs. When I press F5 on line with 
println, for the 1st time it steps into VM.intern, for other times it 
steps into PrintStream.println. Sources for these classes aren't found, 
but I can step out back to main() function.

> Platform information:
> 
> JRE: harmony-jre-580985
> 
> Eclipse: Version: 3.2.2 Build id: M20070212-1330
> 
> OS: Microsoft Windows Server 2003 R2 Standard Edition Service Pack 1
> (Running on a VM)
> 
> The way to debug the application: Debug As -> Debug ..., select Harmony as
> the JRE and put a breakpoint at any line. The program halts at the specified
> breakpoint as expected, but if you press F5 or F6, it throws the NPE. Any
> idea?
> 
> It doesn't have any problem to run the application against Harmony.
> 
> Thanks!
> 
> Works for me too on Windows M3 JDK build with Eclipse 3.3.
>> Andrew: Could you give us the precise steps to reproduce?
>>
>> Regards,
>> Tim
>>
>>
>>
> 
> 


-- 
Gregory


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