Code Advice #15: Name getters properly!

WARNING: This blog entry was imported from my old blog on blogs.sun.com (which used different blogging software), so formatting and links may not be correct.

(See intro for a background and caveats on these coding advice blog entries.)

It's been a while since I've posted Java-coding opinions. But I couldn't resist on this one. The tip itself is straightforward:

A getter method's name should not sound like an action method.

Getter methods and setter methods should not have the same name.

I'm speaking from bitter experience since I just fixed a bug where my code had accidentally been calling a getter method, when I thought I was calling a setter method.
The method in question is java.lang.ProcessBuilder#redirectErrorStream. If you're launching a process, and you want to read its output, you may want to redirect its error output to its standard output such that you only have to read the input from a single source (assuming you don't care to distinguish between output and error.)

Well, my code was initializing the ProcessBuilder:

ProcessBuilder pb = new ProcessBuilder(args);
pb.directory(pwd);
pb.redirectErrorStream();

The problem here is that redirectErrorStream() does NOT redirect the error stream! It just returns false to tell me that it's not yet planning to redirect the error stream. The correct way to do this is

ProcessBuilder pb = new ProcessBuilder(args);
pb.directory(pwd);
pb.redirectErrorStream(true);

That's right - the setter and the getter are overloaded! Ewwwww!!!

This is the kind of thing a bug detection tool like findbugs could detect. It already warns if it sees you doing something similar, like calling String.trim() without storing the return value. Unfortunately, it didn't warn me about this case - so I filed a request. But this was a great reminder to run findbugs on my code again, which turned up some other interesting things to look at...