如何为java调用者声明返回类型为'void'的Kotlin函数？

Question

interface Foo{
  fun bar()
}

class FooImpl implements Foo{
   // should be public void bar()
   public Unit bar(){  
      return Unit.INSTANCE 
      // ^^ implementations should not be forced to return anything 
   }
}

Answer 1

void和void都可以工作，只需跳过单元...

Kotlin接口：

interface Demo {
  fun demoingVoid() : Void?
  fun demoingvoid()
}

实现该接口的Java类：

class DemoClass implements Demo {

    @Override
    public Void demoingVoid() {
        return null; // but if I got you correctly you rather want to omit such return values... so lookup the next instead...
    }

    @Override
    public void demoingvoid() { // no Unit required...

    }
}

fun demo() : Unit { }
fun demo() { }