Lately I have seen quite a few misconceptions regarding how string concatenation is handled in the Java world so I would like to write this short blog entry with a couple of stupid examples in order to show the basics of how it is done.

Note: I am focusing here in the bytecode generated by the Java compiler, regardless any optimization the runtime could apply.

Concatenating constant strings

Imagine we are writing a new class where we have defined three final string fields and we want to add a new method which just returns the sum of the three: