Java varargs method param list vs. array

Question

Varargs:

public static void foo(String... string_array) { ... }

versus

Single array param:

public static void bar(         


        

Answer 1

Another difference is efficiency. Objects that are inside an explicit array won't get invoked. However the parameters of a variable argument list are evaluated when the method is pushed on the stack.

This is apparent when a function call is passed as a parameter that returns the type that is used in the variable argument list.

Example: someMethod( Object... x) anotherMethod( Object [] );

someMethod( a(), b(), c()); // a, b and c will be invoked before you get into the method.

anotherMethod ( new Object[]{a(), b(), c()}); // The methods aren't invoked until the objects are accessed.