What is the difference between immutable and final in java?

Question

I was recently asked this quesion. But was not able to explain concisely what exactly sets both these concepts apart.

For example

Final and Immutable:<

Answer 1

final

The object cannot be changed.

final String s = "Hello";
// Not allowed.
s = "Bye";

immutable

The contents of the object cannot be changed.

BigInteger one = BigInteger.ONE;
// Does not change `one` or `BigInteger.ONE`.
one.add(BigInteger.ONE);
// Have to do it this way.
BigInteger two = one.add(one);