What does $NON-NLS-1$ mean?

Question

In Eclipse source code, I've found some '$NON-NLS-1$' in comments used like that :

private String toolTip = ""; //$NON-NLS-1$

What does that mean ?

Answer 1

They quell a signal that Eclipse issues when it meets string literals (and has been configured to complain).

The design is that UI advice should not be installed as string literals, but preferably sourced from a resource file (so that they can be translated, proofed, etc). Consequently, Eclipse can be configured to identify string literals, so that you don't randomly have consent unexternalized UI strings in the code; nevertheless, there are strings which should not be externalized (such as regexp) and so, //$NON-NLS-1$ supplies you a way to express that point to the compiler.