Use Native Methods
When processing strings, don't hesitate to use specialty methods like
String.indexOf(), String.lastIndexOf(), and their cousins. These are typically
implemented in C/C++ code that easily runs 10-100x faster than doing the same
thing in a Java loop.
The flip side of that advice is that punching through to a native
method is more expensive than calling an interpreted method. Don't use native
methods for trivial computation, if you can avoid it.