Invalid escape sequence (valid ones are \b \t \n \f \r \" \' \ )

Question

I have a problem with a regex in java.

When I try to use this regex:

 ^(?:(?:([01]?\\d|2[0-3]):)?([0-5]?\\d):)?([0-5]?\\d)$  

I g

Answer 1

This should work ^(?:(?:([01]?\\d|2[0-3]):)?([0-5]?\\d):)?([0-5]?\\d)$

The reason is that the listed symbols in the error message have special meaning, but \d is not one of those defined special symbols for using \, this means you have to escape it (by adding an extra \ in front of the symbol).