Java 8 Not able to implement two interfaces because of Multiple Inheritance

Question

I have two contracts (interfaces) both have default method with same name but different return type.

I have to create a Class which should implement both the contract. If I am trying to do it then it is giving me the compilation error.

I can't change the default method of Cotract1 as many classes are implementing Contract1 and the same with Contract2.

Is there anyway by which I can write the class which should have the implementation of both the interfaces, without changing anything in the interface.

Below is the piece of code:

interface Contract1 {
    default String getVersion() {
       return "Beta_10.2.3";
    }
    //....
}
interface Contract2 {
    default Double getVersion() {
        return 11.2;
    }
    //....
}
public class ContractsImplementation implements Contract1, Contract2{

}

Answer 1

Suggestion:

Sanjay, if you do not want to have any default methods in your class like you said, use composition over inheritance.

interface Contract1 {
   default String getVersion() {
      return "Beta_10.2.3";
   }
   //....
}
interface Contract2 {
    default Double getVersion() {
        return 11.2;
    }
    //....
}
public class ContractsImp {

    private class Contract1Imp implements Contract1 {}
    private class Contract2Imp implements Contract2 {}

    private Contract1 contract1 = new Contract1Imp();
    private Contract2 contract2 = new Contract2Imp();
    // Here you can do with contracts whatever you want
    // ...
}