String Buffer v.s. StringBuilder und String

String

String s = "a"; for (int i = 0; i < 500000; i++) { s = s+"a"; } time spent : 181801

StringBuffer

StringBuffer is syncronized and good for thread safety. StringBuffer s = new StringBuffer("a"); for (int i = 0; i < 500000; i++) { s = s.append("a"); } s.toString(); time spent : 20

StringBuilder

StringBuilder s = new StringBuilder("a"); for (int i = 0; i < 500000; i++) { s = s.append("a"); } s.toString(); time spent : 16