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I'm not sure that @NotNull example is appropriate. Java compiler does not add any checks for @NotNull annotations. Those annotations exist for IDE and linting t

I'm not sure that @NotNull example is appropriate. Java compiler does not add any checks for @NotNull annotations. Those annotations exist for IDE and linting tools, compiler doesn't care. May be there are Java-like languages like Lombok or non-standard compilers which do add those checks, but I think that Java decompiler shouldn't do assumptions of these additional tools.

rhdunn 1y ago
https://www.jetbrains.com/help/idea/annotating-source-code.html#disable-nullability-assertions https://www.jetbrains.com/help/idea/annotating-source-code.h... > When you compile your project with IntelliJ IDEA build tool, the IDE adds assertions to all code elements annotated with @NotNull. These assertions will throw an error if the elements happen to be null at runtime.
- bingabingabinga 1y ago
  [dead]
- vbezhenar 1y ago
  That's not java compiler. That's intellij compiler. I'd say that's very weird anti-feature, because your build in IDE and maven will work differently.
  - wokkel 1y ago
    When using Lombok it will use a compiler plugin for this so maven builds have @nonnull generated as if-statements. I dont know if intellij uses their own plugin but they do support Lombok in maven projects, so maybe thats where this is coming from. Afaik intellij has no built in compiler but relies on java .
    - Bjartr 1y ago
      Lombok hijacks the compiler to do it's own thing, and violates the contract Java compiler plugins are supposed to follow. See this comment by an OpenJDK tech lead: https://news.ycombinator.com/item?id=37666793 https://news.ycombinator.com/item?id=37666793
      - lisbbb 1y ago
        I was initially impressed with Lombok and then ran into all the downsides of it and it was institutionally abandoned at one particular firm I was with (100s of devs).
rhdunn 1y ago
I was trying to think of examples. A better example for Java would be something like lambda expressions on functional interfaces. There, the compiler is creating an anonymous object that implements the interface. A reversable decompiler will just see the anonymous class instance whereas an analytical decompiler can detect that it is likely a lambda expression due to it being an anonymous class object implementing a single method interface and is being passed to a function argument that takes that interface as a parameter. In C# yield is implemented as a state machine, so an analytical decompiler could recognise that construct. And yes, for JVM decompilers it could have language heuristics to detect (or be specifically for) Lombok, Scala, Groovy, Kotlin, etc. [1] https://docs.oracle.com/javase/tutorial/java/javaOO/lambdaexpressions.html#approach5 https://docs.oracle.com/javase/tutorial/java/javaOO/lambdaex...

rhdunn 1y ago

https://www.jetbrains.com/help/idea/annotating-source-code.html#disable-nullability-assertions https://www.jetbrains.com/help/idea/annotating-source-code.h... > When you compile your project with IntelliJ IDEA build tool, the IDE adds assertions to all code elements annotated with @NotNull. These assertions will throw an error if the elements happen to be null at runtime.

bingabingabinga 1y ago
[dead]
vbezhenar 1y ago
That's not java compiler. That's intellij compiler. I'd say that's very weird anti-feature, because your build in IDE and maven will work differently.
- wokkel 1y ago
  When using Lombok it will use a compiler plugin for this so maven builds have @nonnull generated as if-statements. I dont know if intellij uses their own plugin but they do support Lombok in maven projects, so maybe thats where this is coming from. Afaik intellij has no built in compiler but relies on java .
  - Bjartr 1y ago
    Lombok hijacks the compiler to do it's own thing, and violates the contract Java compiler plugins are supposed to follow. See this comment by an OpenJDK tech lead: https://news.ycombinator.com/item?id=37666793 https://news.ycombinator.com/item?id=37666793
    - lisbbb 1y ago
      I was initially impressed with Lombok and then ran into all the downsides of it and it was institutionally abandoned at one particular firm I was with (100s of devs).

rhdunn 1y ago

I was trying to think of examples. A better example for Java would be something like lambda expressions on functional interfaces. There, the compiler is creating an anonymous object that implements the interface. A reversable decompiler will just see the anonymous class instance whereas an analytical decompiler can detect that it is likely a lambda expression due to it being an anonymous class object implementing a single method interface and is being passed to a function argument that takes that interface as a parameter. In C# yield is implemented as a state machine, so an analytical decompiler could recognise that construct. And yes, for JVM decompilers it could have language heuristics to detect (or be specifically for) Lombok, Scala, Groovy, Kotlin, etc. [1] https://docs.oracle.com/javase/tutorial/java/javaOO/lambdaexpressions.html#approach5 https://docs.oracle.com/javase/tutorial/java/javaOO/lambdaex...