OnJava8-Examples/interfaces/InterfaceCollision.java

// interfaces/InterfaceCollision.java
// (c)2016 MindView LLC: see Copyright.txt
// We make no guarantees that this code is fit for any purpose.
// Visit http://OnJava8.com for more book information.

interface I1 { void f(); }
interface I2 { int f(int i); }
interface I3 { int f(); }
class C { public int f() { return 1; } }

class C2 implements I1, I2 {
  @Override
  public void f() {}
  @Override
  public int f(int i) { return 1; } // overloaded
}

class C3 extends C implements I2 {
  @Override
  public int f(int i) { return 1; } // overloaded
}

class C4 extends C implements I3 {
  // Identical, no problem:
  @Override
  public int f() { return 1; }
}

// Methods differ only by return type:
//- class C5 extends C implements I1 {}
//- interface I4 extends I1, I3 {}