java - Validating numeric sequence -

i using java , need validate numeric sequence this: 9999/9999.

i tried using regex \\d{4}\\\\d{4}, getting false matches().

my code:

    pattern regex = pattern.compile("\\d{4}\\\\d{4}");      if (!regex.matcher(mysequence).matches()) {         system.out.println("invalid");     } else {         system.out.println("valid");     } 

can me, please?

the regex pattern attempting match backslash rather forward slash character. need use:

pattern regex = pattern.compile("\\d{4}/\\d{4}")