How to overcome “same JVM signature” error when implementing a Java interface?

Question

With the code below, I am getting the following error in IntelliJ IDEA 13.1.6 and Kotlin plugin 0.11.91.AndroidStudio.3:

Platform declaration clash: The foll         


        

Answer 1

You could use @JvmField for instructs the compiler not generate getter/setter, and you can implement your setters and getters. With this your code work well in Java (as attribute getter/setter) and Kotlin as property

Example: JAVA:

public interface Identifiable<ID extends Serializable> 
{
   ID getId();
} 

KOTLIN:

class IdentifiableImpl(@JvmField var id: String) :Identifiable<String> 
{
   override fun getId(): String 
   {
       TODO("not implemented")
   }
}

Answer 2

Another work-around is to declare the properties in an abstract Kotlin class, then write a small java class that extends KotlinClass and implements JavaInterface.

// JavaInterface.java
public interface JavaInterface {
    int getFoo();
    void setFoo(int value);
}

// KotlinClass.kt
abstract class KotlinClass(open var foo : Int = 0) {
}

// JavaAdapter.java
class JavaAdapter extends KotlinClass implements JavaInterface {
    // all code in KotlinClass, but can't implement JavaInterface there
    // because kotlin properties cannot override java methods.
}

Answer 3

IMHO most readable combination is field + explicit interface implementation by the single-expression function (combination of @Renato Garcia's and @Steven Spungin's answers):

Java:

public inteface SomeInterface {
    String getFoo();
}

Kotlin:

class Implementation(@JvmField val foo: String) : SomeInterface {
    override fun getFoo() = foo
}

Answer 4

The annotation feature of Kotlin named @JvmName will solve the duplication problem in Java and Kotlin when having the same signature.

fun function(p: String) {
   // ...
}

// Signature: function(Ljava/lang/String)

With the use of JvmName will be:

@JvmName("functionOfKotlin")
fun function(p: String) {
   // ...
}

// Signature: functionOfKotlin(Ljava/lang/String)

Answer 5

public interface JavaInterface {
    public String getName();
}

public class KotlinClass(val namePrivate: String?) : JavaInterface {

private var name = namePrivate

    override fun getName(): String? {
        return name
    }
}

Answer 6

Rename the variable to something else, or make it private if u dont want it to be public.