Conversion String concordinate (using +) to StingBuffer Class are no longer needed in Java 1.5?. One of my friend is saying this to me.. I tried a simple example and i can still see the performance difference... is this statement is true.
I don't know exactly what you mean with your question, but code that concatenates strings with + is still converted to operations with StringBuilder by the Java compiler in Java 5. Note that it's no longer using StringBuffer, but StringBuilder.
StringBuilder is almost the same as StringBuffer, except that it's not synchronized (similar to the difference between ArrayList and Vector). StringBuffer is a legacy class that should not be used anymore in favour of StringBuilder.
Maybe your friend read something about StringBuffer being obsolete since Java 5 and got confused with this.