Need help with Kotlin Java interop ``` Tasks kt abstract cla kotlinlang #announcements

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Title

a

armaxis

03/12/2019, 11:32 PM

Need help with Kotlin-Java interop!

//Tasks.kt
abstract class Foo : Callable<Unit> {   
    override fun call() { bar() }
    abstract fun bar()
}

//Manager.java
public class FooChild extends Tasks.Foo {
    @Override public void bar() { //haha }
}

Class FooChild is highlighed as Error with message: 'call()' in 'Tasks.Foo' clashes with 'call()' in 'java.util.concurrent.Callable'; attempting to use incompatible return type

Somewhy it creates another call() method marked as

public synthetic bridge

. Here's bytecode:

// access flags 0x1
public call()V
 L0
  LINENUMBER 93 L0
  ALOAD 0
  INVOKEVIRTUAL Tasks$Foo.bar ()V
  RETURN
 L1
  LOCALVARIABLE this LTasks$Foo; L0 L1 0
  MAXSTACK = 1
  MAXLOCALS = 1
// access flags 0x1041
public synthetic bridge call()Ljava/lang/Object;
 L0
  LINENUMBER 91 L0
  ALOAD 0
  INVOKEVIRTUAL Tasks$Foo.call ()V
  GETSTATIC kotlin/Unit.INSTANCE : Lkotlin/Unit;
  ARETURN
  MAXSTACK = 1
  MAXLOCALS = 1

d

Dico

03/13/2019, 4:09 AM

In java:

public kotlin.Unit call()

a

armaxis

03/13/2019, 7:02 AM

Are you suggesting to override the method

Call

?

d

Dico

03/14/2019, 1:12 AM

What I'm suggesting is that you dont use void but the actual return type of the function. I misread the function name though.

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