Java String Concatenation

In Java, you use either the String concatenation + operator or StringBulder class methods such as append. Since Java compilers frequently create intermediate objects when the + operator is used and don't when StringBuilder.append is used, the append method is faster than the + operator.

In general, use the convenience of a + operator when speed is not an issue. For example, when concatenating a small number of items and when code isn't executed very frequently. A decent rule of thumb is to use the + operator for general purpose programming and then optimize the + operator with StringBuilder.append as needed.

Simple + operator example:

System.out.println("Hello" + " " + "Mike.");

Using StringBuilder example:

StringBuilder myMsg = new StringBuilder();
 

myMsg.append("Hello ");

myMsg.append("Mike.");

 
System.out.println(myMsg);