What's the difference between instance method reference types in Java 8?

Question

So Java 8 introduces method references and the docs describe the four types.

My question is what\'s the difference between the two instance types?

Answer 1

With this they mean that you have the following:

1) Can be for example this::someFunction;, this will return the someFunction reference of the current object.

2) Can be for example String::toUpperCase, this will return the toUpperCase method of String in general.

I am not sure if there is an actual difference in behaviour, I think it is just like you can also call static methods on instance variables.