The plus symbol can be used as three distinct operators in Java:
- as the unary Plus operator, if there is no operand before the +
- as the binary Addition operator, if there are two numeric operands
- the binary Concatenation operator, if there are two operands, and at least one of them is a String
In a simple example, the Concatenation operator joins two strings to give a third string.
String s1 = "a String"; String s2 = "This is " + s1; // s2 contains "This is a String"