concatenation « StringBuffer « Java Data Type Q&A

1. Why to use StringBuffer in Java instead of the string concatenation operator    stackoverflow.com

Someone told me it's more efficient to use StringBuffer to concatenate strings in Java than to use the + operator for Strings. What happens under the hood when you do that? ...

2. Java: StringBuffer & Concatenation    stackoverflow.com

I'm using StringBuffer in Java to concat strings together, like so:

StringBuffer str = new StringBuffer();

str.append("string value");