Strings

1. String s = "f" + "o" + "o"

is faster than

String s = "f";
s+="o";
s+="o";

2. The comparison
   ('a' == s.charAt(0))

is faster than

s.startsWith("a");

3. The StringBuffer default capacity is 16. If your string is going to be larger than that, you might as well reserve a larger capacity by passing a realistic length such asStringBuffer sb = new StringBuffer(1024);