StringBuffer?

[Zordid]

It's a very well known fact, that one should not use StringBuffers. StringBuffers have a huge overhead for synchronization purposes that are not needed here. You should replace those with StringBuilders and even consider not using them at all.

If there are no loops, a simple String a = "Hello, "+ b+ "world!" internally uses a StringBuilder by itself without you worrying about it in the first place...