Hi Peter,
On 7/07/2018 2:10 AM, Peter Levart wrote:
Hi,
On 07/05/2018 01:01 AM, David Holmes wrote:
I dispute "they will understand this might have happened in another
thread".
What if the stack trace was like the following...
Yes your suggestion makes it much clearer.
But ... my whole objection here is doing all this extraneous execution
of Java code in response to the initial exception. The more Java code we
execute the more likely we will hit secondary exceptions and the greater
the possibility of unintended interactions that might lead back to the
class that can't be initialized. I just don't think this level of effort
is warranted.
Cheers,
David
-----
Before patch:
1st attempt [ForkJoinPool.commonPool-worker-3]:
java.lang.ExceptionInInitializerError
at ClinitFailure.lambda$main$0(ClinitFailure.java:20)
at
java.base/java.util.concurrent.CompletableFuture$AsyncRun.run(CompletableFuture.java:1736)
at
java.base/java.util.concurrent.CompletableFuture$AsyncRun.exec(CompletableFuture.java:1728)
at
java.base/java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:290)
at
java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1020)
at
java.base/java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1656)
at
java.base/java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1594)
at
java.base/java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:177)
Caused by: java.lang.RuntimeException: Can't get it!
at ClinitFailure$Faulty.<clinit>(ClinitFailure.java:12)
... 8 more
Caused by: java.lang.ArrayIndexOutOfBoundsException: Index 1 out of
bounds for length 0
at ClinitFailure$Faulty.<clinit>(ClinitFailure.java:10)
... 8 more
2nd attempt [ForkJoinPool.commonPool-worker-5]:
java.lang.NoClassDefFoundError: Could not initialize class
ClinitFailure$Faulty
at ClinitFailure.lambda$main$1(ClinitFailure.java:28)
at
java.base/java.util.concurrent.CompletableFuture$UniRun.tryFire(CompletableFuture.java:783)
at
java.base/java.util.concurrent.CompletableFuture$Completion.exec(CompletableFuture.java:479)
at
java.base/java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:290)
at
java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1020)
at
java.base/java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1656)
at
java.base/java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1594)
at
java.base/java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:177)
After patch:
1st attempt [ForkJoinPool.commonPool-worker-3]:
java.lang.ExceptionInInitializerError
at ClinitFailure.lambda$main$0(ClinitFailure.java:18)
at
java.base/java.util.concurrent.CompletableFuture$AsyncRun.run(CompletableFuture.java:1736)
at
java.base/java.util.concurrent.CompletableFuture$AsyncRun.exec(CompletableFuture.java:1728)
at
java.base/java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:290)
at
java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1020)
at
java.base/java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1656)
at
java.base/java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1594)
at
java.base/java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:177)
Caused by: java.lang.RuntimeException: Can't get it!
at ClinitFailure$Faulty.<clinit>(ClinitFailure.java:10)
... 8 more
Caused by: java.lang.ArrayIndexOutOfBoundsException: Index 1 out of
bounds for length 0
at ClinitFailure$Faulty.<clinit>(ClinitFailure.java:8)
... 8 more
2nd attempt [ForkJoinPool.commonPool-worker-5]:
java.lang.NoClassDefFoundError: Could not initialize class
ClinitFailure$Faulty
at
java.base/java.lang.ClassLoader.throwReinitException(ClassLoader.java:3062)
at ClinitFailure.lambda$main$1(ClinitFailure.java:25)
at
java.base/java.util.concurrent.CompletableFuture$UniRun.tryFire(CompletableFuture.java:783)
at
java.base/java.util.concurrent.CompletableFuture$Completion.exec(CompletableFuture.java:479)
at
java.base/java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:290)
at
java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1020)
at
java.base/java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1656)
at
java.base/java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1594)
at
java.base/java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:177)
Caused by: java.lang.ExceptionInInitializerError: 11 ms ago in thread
ForkJoinPool.commonPool-worker-3
at ClinitFailure.lambda$main$0(ClinitFailure.java:18)
at
java.base/java.util.concurrent.CompletableFuture$AsyncRun.run(CompletableFuture.java:1736)
at
java.base/java.util.concurrent.CompletableFuture$AsyncRun.exec(CompletableFuture.java:1728)
... 5 more
Caused by: java.lang.RuntimeException: Can't get it!
at ClinitFailure$Faulty.<clinit>(ClinitFailure.java:10)
... 8 more
Caused by: java.lang.ArrayIndexOutOfBoundsException: Index 1 out of
bounds for length 0
at ClinitFailure$Faulty.<clinit>(ClinitFailure.java:8)
... 8 more
This is what gets printed by the sample program:
public class ClinitFailure {
static class Faulty {
static {
try {
int i = (new int[0])[1];
} catch (Exception e) {
throw new RuntimeException("Can't get it!", e);
}
}
}
public static void main(String[] args) throws Exception {
CompletableFuture.runAsync(() -> {
try {
new Faulty();
} catch (Throwable e) {
System.out.printf("\n1st attempt [%s]:\n\n",
Thread.currentThread().getName());
e.printStackTrace(System.out);
}
}).thenRunAsync(() -> {
try {
new Faulty();
} catch (Throwable e) {
System.out.printf("\n2nd attempt [%s]:\n\n",
Thread.currentThread().getName());
e.printStackTrace(System.out);
}
}).join();
}
}
When the following patch is applied:
http://cr.openjdk.java.net/~plevart/jdk-dev/8203826_NoClassDefFoundError.cause/webrev.01/
I took Volker's patch and modified it a bit:
- The logic to construct and throw NoClassDefFoundError and to record
initial <clinit> exception is in java now. It uses ClassLoaderValue
internal API to save the chains of exception(s) for faulty classes. It
is easier to do such logic in Java and less error prone.
- The chain of original <clinit> exception(s) is replaced with
substitutes that mimic .toString() and .printStackTrace() methods of
original chain, but don't reference any classes outside bootstrap class
loader
- The replacement chain of original exceptions adds a custom message
insert into the top exception as a hint to the user:
java.lang.ExceptionInInitializerError: 11 ms ago in thread
ForkJoinPool.commonPool-worker-3
So, what do you think of this one?
Regards, Peter
