My requirement is to find if a unknown string of 4 chars is repeating of a string of length 16.
So basically, INPUT : "shgtHellorhecHello" Should return true.
Only known thing to us is that the repeating substring if of 4 chars and the full string is if 16 chars.
Please help
You can do this with a Regular Expression:
String searchString = 'shgtHellorhecHello';
Pattern p = Pattern.compile('(.{4}).*\\1');
Boolean repeatFound = p.matcher(searchString).find();
This pattern matches "any four characters ((.{4})), separated by any number of characters (.*), then those same four characters from the first group (\\1)".
