Bugzilla – Full Text Bug Listing
| Summary: | .class file signature contains invalid exclamation point causing external tools (findbugs) to die | ||||||
|---|---|---|---|---|---|---|---|
| Product: | [Eclipse Project] JDT | Reporter: | Frits Jalvingh <jal> | ||||
| Component: | Core | Assignee: | JDT-Core-Inbox <jdt-core-inbox> | ||||
| Status: | CLOSED DUPLICATE | QA Contact: | |||||
| Severity: | normal | ||||||
| Priority: | P3 | CC: | stephan.herrmann | ||||
| Version: | 4.5.1 | ||||||
| Target Milestone: | --- | ||||||
| Hardware: | PC | ||||||
| OS: | Linux | ||||||
| Whiteboard: | |||||||
| Attachments: |
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Hi Frits,
what you are seeing is the "signature" of a wildcard capture.
JVMS 4.7.9.1. doesn't expect a capture in the byte code.
The offending entry in the byte code is:
private static void lambda$0(java.util.List, to.etc.other.IIdentifyable);
descriptor: (Ljava/util/List;Lto/etc/other/IIdentifyable;)V
flags: ACC_PRIVATE, ACC_STATIC, ACC_SYNTHETIC
Code:
stack=2, locals=2, args_size=2
0: aload_0
1: aload_1
2: invokeinterface #77, 1 // InterfaceMethod to/etc/other/IIdentifyable.ge
tId:()Ljava/lang/Object;
7: checkcast #83 // class java/lang/Long
10: invokeinterface #119, 2 // InterfaceMethod java/util/List.add:(Ljava/lan
g/Object;)Z
15: return
LineNumberTable:
line 28: 0
LocalVariableTable:
Start Length Slot Name Signature
0 16 1 a Lto/etc/other/IIdentifyable;
LocalVariableTypeTable:
Start Length Slot Name Signature
0 16 1 a !+Lto/etc/other/IIdentifyable<Ljava/lang/Long;>;
Read: the lambda expression inside set(List<? extends IIdentifyable<Long>>) has a local variable, who's generic type is a capture.
Now we have a problem: we need to record the type of the local variable in the LocalVariableTypeTable but JVMS doesn't tell us how to encode the capture, bummer!
*** This bug has been marked as a duplicate of bug 494198 ***
Thanks, Stephan, for the detailed explanation in the bugs and on stackoverflow. I did try to find those before I reported the bug, but sadly enough the stackoverflow article would be unfindable using exclamation point/mark ;) I did circumvent the issue in FindBugs; I'll try to send the fix to that project. |
Created attachment 262729 [details] Workspace that shows the problem The compiler seems to generate an invalid signature: #124 = Utf8 !+Lto/etc/other/IIdentifyable<Ljava/lang/Long;>; which starts with an exclamation point. This caused problems with tools like FindBugs - which die on that. For some reason the class does not cause trouble in other ways- the JVM seems to be fine with it. I extracted the code that causes this; the problem can be seen by looking at the byte code for the class "SavedRecordList" using javap -v -p To reproduce: - untar the attachment - start Eclipse and import projects - wait for compile to finish - use javap -v -p to decompile the class file.