Re: [jdt-dev] [ECJ] Heap Increases from the 1.7 to 1.8 Compiler Option

["Alexander Kriegisch" <alexander@xxxxxxxxxxxxxx>]

Hi Volodymyr.

Sorry for the slightly OT question, but as you mentioned it, ...

> Using version 4.20 (last to be built with Java 8), the application
> needs a heap space of 5GB to compile successfully with 1.8.
> (Unfortunately, I cannot test any newer ECJ versions)

Why can you not use any more recend ECJ version? Source and target 8
should still be supported, even if you run the build itself on e.g. JDK
11, 17 or 21.

-- 
Alexander Kriegisch
https://scrum-master.de


Volodymyr Siedlecki via jdt-dev schrieb am 17.11.2023 21:56 (GMT +07:00):
> 
> 
> Hello,
> 
> 
> I need assistance with the Eclipse Compiler, and I'm hoping someone could
> provide feedback.
> 
> 
> The ECJ in our code used to compile translated JSPs, but it hangs on a
> particularly large application if the 1.8 source/target is set. Using
> version 4.20 (last to be built with Java 8), the application needs a heap
> space of 5GB to compile successfully with 1.8. (Unfortunately, I cannot
> test any newer ECJ versions)
> 
> 
> However, if 1.7 is selected, then only 1GB of heap is required to compile
> successfully. I don't understand why an additional 4GB is required for
> source / target 1.8. I understand there are new language features in 1.8,
> such as Lambdas, but it's a dramatic heap increase.
> 
> 
> We can just increase the heap to avoid this problem, but I would like to
> know why. Has anyone experienced this or knows about this scenario? No out
> of memory error is reported in the logs, but the threads just hang.
> 
> 
> Here's the stack trace for when the error occurs:
> 
> 
> CPU usage total: 212.539956241 secs, current category="Application"
> 
> Heap bytes allocated since last GC cycle=0 (0x0)
> 
> Java callstack:
> 
> at
> org/eclipse/jdt/internal/compiler/lookup/InferenceContext18.substitute(InferenceContext18.java:245(Compiled
> Code))
> 
> at
> org/eclipse/jdt/internal/compiler/lookup/InferenceContext18.inferInvocationType(InferenceContext18.java:398(Compiled
> Code))
> 
> at
> org/eclipse/jdt/internal/compiler/lookup/ParameterizedGenericMethodBinding.computeCompatibleMethod18(ParameterizedGenericMethodBinding.java:271(Compiled
> Code))
> 
> at
> org/eclipse/jdt/internal/compiler/lookup/ParameterizedGenericMethodBinding.computeCompatibleMethod(ParameterizedGenericMethodBinding.java:92(Compiled
> Code))
> 
> at
> org/eclipse/jdt/internal/compiler/lookup/Scope.computeCompatibleMethod(Scope.java:844(Compiled
> Code))
> 
> at
> org/eclipse/jdt/internal/compiler/lookup/Scope.computeCompatibleMethod(Scope.java:801(Compiled
> Code))
> 
> at
> org/eclipse/jdt/internal/compiler/lookup/Scope.findMethod0(Scope.java:1759(Compiled
> Code))
> 
> at
> org/eclipse/jdt/internal/compiler/lookup/Scope.findMethod(Scope.java:1660(Compiled
> Code))
> 
> at
> org/eclipse/jdt/internal/compiler/lookup/Scope.getMethod(Scope.java:3048(Compiled
> Code))
> 
> at
> org/eclipse/jdt/internal/compiler/ast/MessageSend.findMethodBinding(MessageSend.java:1018(Compiled
> Code))
> 
> at
> org/eclipse/jdt/internal/compiler/ast/MessageSend.resolveType(MessageSend.java:839(Compiled
> Code))
> 
> at
> org/eclipse/jdt/internal/compiler/ast/Expression.resolve(Expression.java:1113(Compiled
> Code))
> 
> at
> org/eclipse/jdt/internal/compiler/ast/Block.resolve(Block.java:131(Compiled
> Code))
> 
> at
> org/eclipse/jdt/internal/compiler/ast/IfStatement.resolveIfStatement(IfStatement.java:291(Compiled
> Code))
> 
> at
> org/eclipse/jdt/internal/compiler/ast/IfStatement.resolve(IfStatement.java:317(Compiled
> Code))
> 
> at
> org/eclipse/jdt/internal/compiler/ast/AbstractMethodDeclaration.resolveStatements(AbstractMethodDeclaration.java:661(Compiled
> Code))
> 
> at
> org/eclipse/jdt/internal/compiler/ast/MethodDeclaration.resolveStatements(MethodDeclaration.java:362(Compiled
> Code))
> 
> at
> org/eclipse/jdt/internal/compiler/ast/AbstractMethodDeclaration.resolve(AbstractMethodDeclaration.java:570(Compiled
> Code))
> 
> at
> org/eclipse/jdt/internal/compiler/ast/TypeDeclaration.resolve(TypeDeclaration.java:1512(Compiled
> Code))
> 
> at
> org/eclipse/jdt/internal/compiler/ast/TypeDeclaration.resolve(TypeDeclaration.java:1637(Compiled
> Code))
> 
> at
> org/eclipse/jdt/internal/compiler/ast/CompilationUnitDeclaration.resolve(CompilationUnitDeclaration.java:667(Compiled
> Code))
> 
> at org/eclipse/jdt/internal/compiler/Compiler.process(Compiler.java:902)
> 
> at
> org/eclipse/jdt/internal/compiler/Compiler.processCompiledUnits(Compiler.java:575)
> 
> at org/eclipse/jdt/internal/compiler/Compiler.compile(Compiler.java:475)
> 
> at org/eclipse/jdt/internal/compiler/Compiler.compile(Compiler.java:426)
> 
> at
> com/ibm/ws/jsp/translator/compiler/JDTCompiler.compile(JDTCompiler.java:178)
> 
> 
> I've attached a screenshot with additional information. 
> 
> 
> Any guidance is appreciated.
> 
> 
> Thank you,
> 
> 
> Volodymyr
> 
>