[JDK-8210527] NullPointerException in jstack exception rendering

[Stuart Marks]

The jshell mailing list is kulla-dev at openjdk.java.net. I'm cc'ing that list and 
bcc'ing jdk-dev. (Yes, the name "kulla-dev" is quite opaque. Sorry.)

s'marks

On 8/19/19 1:10 PM, Steven Schlansker wrote:
> Hello jdk-dev, (hopefully this is the best list, I did not see a jshell-dev)
> 
> I spent most of my Friday diagnosing a confusing issue
> https://bugs.java.com/bugdatabase/view_bug.do?bug_id=JDK-8229863
> 
> which turned out to be a duplicate of JDK-8210527
> Unfortunately it's been open most of a year with no progress.
> 
> The fix is seemingly trivial:
> 
> diff -r 31b7274c7b9e src/jdk.jshell/share/classes/jdk/jshell/Eval.java
> --- a/src/jdk.jshell/share/classes/jdk/jshell/Eval.java Fri Aug 09 03:36:59 2019 +0200
> +++ b/src/jdk.jshell/share/classes/jdk/jshell/Eval.java Mon Aug 19 13:06:57 2019 -0700
> @@ -1106,7 +1106,7 @@
>                   Snippet sn = outer.wrapLineToSnippet(wln);
>                   String file = "#" + sn.id();
>                   elems[i] = new StackTraceElement(klass, method, file, line);
> -            } else if (r.getFileName().equals("<none>")) {
> +            } else if ("<none>".equals(r.getFileName())) {
>                   elems[i] = new StackTraceElement(r.getClassName(), r.getMethodName(), null, r.getLineNumber());
>               } else {
>                   elems[i] = r;
> 
> I verified this fix against jdk13 tip.  Before:
> 
> Unexpected exception reading startup: java.lang.NullPointerException
> java.lang.NullPointerException
> 	at jdk.jshell/jdk.jshell.Eval.translateExceptionStack(Eval.java:1109)
> 	at jdk.jshell/jdk.jshell.Eval.asEvalException(Eval.java:907)
> 	at jdk.jshell/jdk.jshell.Eval.declare(Eval.java:888)
> 	at jdk.jshell/jdk.jshell.Eval.eval(Eval.java:140)
> 	at jdk.jshell/jdk.jshell.JShell.eval(JShell.java:493)
> 	at jdk.jshell/jdk.internal.jshell.tool.JShellTool.processSource(JShellTool.java:3558)
> 	at jdk.jshell/jdk.internal.jshell.tool.JShellTool.processSourceCatchingReset(JShellTool.java:1305)
> 	at jdk.jshell/jdk.internal.jshell.tool.JShellTool.processInput(JShellTool.java:1203)
> 	at jdk.jshell/jdk.internal.jshell.tool.JShellTool.run(JShellTool.java:1176)
> 	at jdk.jshell/jdk.internal.jshell.tool.JShellTool.startUpRun(JShellTool.java:1143)
> 	at jdk.jshell/jdk.internal.jshell.tool.JShellTool.resetState(JShellTool.java:1099)
> 	at jdk.jshell/jdk.internal.jshell.tool.JShellTool.start(JShellTool.java:933)
> 	at jdk.jshell/jdk.internal.jshell.tool.JShellToolBuilder.start(JShellToolBuilder.java:254)
> 	at jdk.jshell/jdk.internal.jshell.tool.JShellToolProvider.run(JShellToolProvider.java:94)
> 	at JshellNpe.main(JshellNpe.java:20)
> 
> After,
> 
> Exception java.lang.IllegalStateException: This helpful exception message is lost
>        at JshellNpe.lambda$2 (JshellNpe.java:27)
>        at $Proxy0.hashCode (Unknown Source)
>        at JshellNpe.init (JshellNpe.java:28)
>        at (#s1:1)
> 
> Much better!
> 
> What can I do to help move this issue forward to resolution?
> 
> thanks,
> Steven
>