- 80 characters
- cmd + shift + F to auto-format existing code
From Java 7 for Absolute Beginners:
To make your programming simpler and easier (and not drive other programmers crazy), keep your lines (both statements and declarations) as short as possible. For historical reasons, 80 characters is often used as a suggested limit for the length of a line. If you get to 80 characters, find a way to divide the line into two lines. (The 80-character value comes from punch cards having 80 characters.) You can certainly have longer lines (and there are times when it’s acceptable), but hold down on really long lines, for sanity’s sake.
(Java 7 for Absolute Beginners: chapter 2)
This means that the width of your code blocks should support 80 characters. I believe this is about 600px, but I’m not sure.