From a purist view one could argue that inheritance doesn't belong in OO in the first place. Alan Kay's first descriptions of Smalltalk & OOP did not include inheritance concepts.
class A {
public int field1;
public void method1() {
System.out.println("A");
}
public void method2() {
System.out.println("A");
}
}
class B extends A {
public int field2;
public void method1() {
System.out.println("B");
}
}
interface C {
public void method1() {}
public void method2() {}
}
class A implements C {
public int field1;
public void method1() {
System.out.println("A");
}
public void method2() {
System.out.println("A");
}
}
class B implements C {
public A a;
public int field2;
public void method1() {
System.out.println("B");
}
public void method2() {
a.method();
}
}
The upshot is that to teach OOP in Java, say, you need to talk about significant parts of the inheritance machinery just to get dynamic dispatch, perhaps later cautioning against implementation inheritance and even interface inheritance.
In Smalltalk, you can talk dynamic dispatch without messing around with inheritance at all.
For a statically typed language where dynamic dispatch is free from inheritance graphs (sometimes described by saying that subtyping is not inheritance) see Ocaml's structural subtyping via row polymorphic records (bit of a mouthful --- but I need to differentiate from Ocaml's module system which is structurally subtyped and supports inheritance!)