Programmer's Guide to Java™ Certification, A: A Comprehensive Primer, Second Edition

3.18. Passing Primitive Data Values

When the actual parameter is a variable of a primitive data type, the value of the variable is copied to the formal parameter at method invocation. Since formal parameters are local to the method, any changes made to the formal parameter will not be reflected in the actual parameter after the call completes.

Note that the actual parameter can be an expression that is evaluated first, and the resulting value is then passed.

Type conversions between actual and formal parameters of primitive data types are similar to those for numeric assignment conversions (i.e., widening primitive conversions are implicitly applied). However, for parameter passing there are no implicit narrowing conversions (see Section 3.4 ...