Obsolete Java Optimization Tips
People replacing String a = "this" + var1 + " is " + var2;
with multiple calls to StringBuilder or StringBuffer. It actually already uses StringBuilder behind the scenes.
The final modifier on methods and method parameters doesn't help with the performance at all.
Also, the Java HotSpot wiki gives a good overview of the optimizations used by HotSpot and how to efficiently use them in Java code.