NullPointerException when parsing log

[punx120]

Hi,

Using the latest code of jitwatch - I have a NPE in ParseUtil.java because componentType is null: if (componentType.isAssignableFrom(sigParamClass))

I added a simple if and it seems that memParamClass is "boolean".

I'm running 1.8.0 192.

Let me know if need something else.

Thanks

[chriswhocodes]

Hi @punx120, thank you for reporting this bug. Please could you post the stack trace here so I can understand the code path taken to this NPE?

Many thanks,

Chris

[punx120]

Here you go:

    Exception in thread "Thread-4" java.lang.NullPointerException
    at org.adoptopenjdk.jitwatch.util.ParseUtil.paramClassesMatch(ParseUtil.java:548)
    at org.adoptopenjdk.jitwatch.model.AbstractMetaMember.matchesSignature(AbstractMetaMember.java:197)
    at org.adoptopenjdk.jitwatch.model.JITDataModel.findMetaMember(JITDataModel.java:223)
    at org.adoptopenjdk.jitwatch.util.ParseUtil.findMemberWithSignature(ParseUtil.java:339)
    at org.adoptopenjdk.jitwatch.parser.AbstractLogParser.findMemberWithSignature(AbstractLogParser.java:246)
    at org.adoptopenjdk.jitwatch.parser.AbstractLogParser.handleMember(AbstractLogParser.java:468)
    at org.adoptopenjdk.jitwatch.parser.AbstractLogParser.handleMethodLine(AbstractLogParser.java:462)
    at org.adoptopenjdk.jitwatch.parser.AbstractLogParser.handleTagQueued(AbstractLogParser.java:369)
    at org.adoptopenjdk.jitwatch.parser.hotspot.HotSpotLogParser.handleTag(HotSpotLogParser.java:307)
    at org.adoptopenjdk.jitwatch.parser.hotspot.HotSpotLogParser.parseLogCompilationLines(HotSpotLogParser.java:135)
    at org.adoptopenjdk.jitwatch.parser.hotspot.HotSpotLogParser.parseLogFile(HotSpotLogParser.java:111)
    at org.adoptopenjdk.jitwatch.parser.AbstractLogParser.processLogFile(AbstractLogParser.java:362)
    at org.adoptopenjdk.jitwatch.ui.main.JITWatchUI$1.run(Unknown Source)

`

[chriswhocodes]

Hi @punx120 Would you mind doing a clean git clone and build of JITWatch? The line numbers in your stack trace don't match the latest source code so I just need to make sure you're using the latest source.

git clone https://github.com/AdoptOpenJDK/jitwatch
cd jitwatch
mvn clean package

I do agree that it is possible for an NPE on that check since getComponentType can return null but I would like to understand how it got into the state where it thought it was parsing a varargs parameter:

// check assignable
Class<?> componentType = memParamClass.getComponentType();

if (componentType.isAssignableFrom(sigParamClass))

Could you possibly provide the log file you were parsing please?

Thanks,

Chris

[chriswhocodes]

I've added a null check to the isAssignableFrom test.

[punx120]

Thank you chris.

The initial stack trace was probably taken with an old version - but when i re-ran it with the latest - I had a similar stack trace.

This happened when parsing a log from one of the app at my job - and unfortunately, i'm afraid it'd be difficult to share it.

[chriswhocodes]

I've re-opened the issue. Can you post the new stack trace please? Thanks, Chris

[punx120]

You mean with a version just before your "last" commit?

[chriswhocodes]

Hi @punx120 I mean could you show me the stack trace you get when you test with the very latest commit that includes the guard I added.

If it is still throwing exceptions with this guard I will investigate further.

Thanks,

Chris

[punx120]

Sorry for the confusion - here's what happened:

1. Parse a log file with old version - NPE, stack trace pasted above
2. Tried to parse the same log with latest - crashed too
3. Built jitwatch locally with a patch similar to the one your committed - no crash

I haven't tried with a version built from master, but i'm fairly confident it won't crash. I can give it a try if you want. I can also try to give you a stack trace with a verison built before the commit.

Long story short, I think it's fine to close that issue.

[chriswhocodes]

OK thanks for confirming. Closing this issue.