How can you extend Java to introduce passing by reference?

Question

Java is pass-by-value. How could you modify the language to introduce passing by reference (or some equivalent behavior)?

Take for example something like

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Answer 1

There are several ways to write Java code as effectively pass-by-reference, even within the standard pass-by-value conventions.

One approach is to use instance or static variables whose scope includes a particular method, in lieu of explicit parameters. The variables which are being modified could be included in the comments, if you really want to mention their names at the beginning of a method.

The disadvantage with this approach is that the scope of these variables would need to encompass the entire class in question, rather than only the method. If you would like to restrict the variables' scopes more precisely, you could always modify them using getter and setter methods rather than as parameters.

Having worked with both Java and C/C++, I don't think Java's supposed inflexibility in being pass-by-value only is a big deal--for any programmers who know what happens to the variables, there are reasonable workarounds that can accomplish the same things functionally.