Java8 method reference

Java8MethodRef

class Java8MethodRef {

    interface Equality1 {
        boolean eq(Object a);
    }

    interface Equality2 {
        boolean eq(Object a, Object b);
    }

    interface Equality3 {
        boolean eq(Object a, Object b, Object c);
    }

    public void compatibleTypes() {
        Equality2 a = Object::equals;
    }
    
    public void incompatibleTypes() {
//        invalid method reference
//        non-static method equals(java.lang.Object) cannot be referenced from a static context
        Equality1 e1 = Object::equals;

//        incompatible types: invalid method reference
//        method equals in class java.lang.Object cannot be applied to given types
//        required: java.lang.Object
//        found: java.lang.Object,java.lang.Object,java.lang.Object
//        reason: actual and formal argument lists differ in length
        Equality3 e = Object::equals;
    }

}