public final boolean isDefaultOrStaticInterfaceMethod() {
    return (classFile.getAccessFlags() & AccessFlags.ACC_INTERFACE) != 0 && !getNat().isClassInit();
  }
Tests whether the method is being defined on an interface.

@return true if the method is being defined on an interface.
android/android_framework/dex-maker/src/main/java/com/android/dx/cf/code/ConcreteMethod.java