Hi,
Our company is a long time Wicket user on a large code base (10+ years,
>600k loc) and ever since lambdas got introduced in JDK 8, our Wicket
applications have occasionally been plagued by random crashes during
Wicket Page deserialization like this:
|Caused by: java.lang.reflect.InvocationTargetException at
java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:109)
at java.base/java.lang.reflect.Method.invoke(Method.java:580) at
com.vodecc.voipmng.boundary.wicket.WicketApplication$5.lambda$get$0(WicketApplication.java:864)
... 63 more Caused by: java.lang.ClassCastException: cannot assign
instance of java.lang.invoke.SerializedLambda to field
<someClass>.<someFieldWithTypeIModel> of type
org.apache.wicket.model.IModel at
java.base/java.io.ObjectStreamClass$FieldReflector.setObjFieldValues(ObjectStreamClass.java:2096)
at
java.base/java.io.ObjectStreamClass$FieldReflector.checkObjectFieldValueTypes(ObjectStreamClass.java:2060)
at
java.base/java.io.ObjectStreamClass.checkObjFieldValueTypes(ObjectStreamClass.java:1349)
at
java.base/java.io.ObjectInputStream$FieldValues.defaultCheckFieldValues(ObjectInputStream.java:2697)
at
java.base/java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:2498)
at
java.base/java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2284)
at
java.base/java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1762)
at
java.base/java.io.ObjectInputStream$FieldValues.<init>(ObjectInputStream.java:2618)
at
java.base/java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:2469)
at
java.base/java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2284)
at
java.base/java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1762)
at
java.base/java.io.ObjectInputStream.readObject(ObjectInputStream.java:540)
at
java.base/java.io.ObjectInputStream.readObject(ObjectInputStream.java:498)
at java.base/java.util.ArrayList.readObject(ArrayList.java:981) at
java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
at java.base/java.lang.reflect.Method.invoke(Method.java:580) |
The offending member field in this particular crash has a type of
'IModel<String>'.
With "random crashes" I mean that the same code sometimes works and
sometimes crashes, seemingly dependent on the order in which
(capturing?) lambdas are created or called.
I did spent some time looking into this and found quite a few
*unresolved* JDK bugs related to ClassCastExceptions during lambda
serialization:
https://bugs.openjdk.org/browse/JDK-8154236
https://bugs.openjdk.org/browse/JDK-8208752
https://bugs.openjdk.org/browse/JDK-8275387
https://bugs.openjdk.org/browse/JDK-8174864
https://bugs.openjdk.org/browse/JDK-8174865
A comment on JDK-8275387 seemed especially enlightening: "The root cause
is always the same: java.lang.invoke.SerializedLambda can not hold
enough information to correctly identify the which lambda should be
(de-)serialized". This all points to
https://bugs.openjdk.org/browse/JDK-8174864 as the root of the problem.
That ticket mentions that currently, lambda serialization is a lossy
transformation since only the first invocation of any unique
"serialization key" will work (which would explain the randomness we
observed).
We currently "fix" our crashes by using anonymous classes instead of
lambda expressions but obviously this is not ideal - especially since
(given enough indirections) it's quite hard to find out where the lambda
causing the deserialization crash originated from.
Cheers,
Tobias
||
