Strings are immutable - that means I should never use += and only StringBuffer?

Question

Strings are immutable, meaning, once they have been created they cannot be changed.

So, does this mean that it would take more memory if you append things with += th

Answer 1

Yes you would and that is exactly why you should use StringBuffer to concatenate alot of Strings.

Also note that since Java 5 you should also prefer StringBuilder most of the time. It's just some sort of unsynchronized StringBuffer.