How do I check if a Java String contains at least one capital letter, lowercase letter, and number?

Question

I know that I could do this with a series of for loops that iterate through the string but that would be terrible programming. Well, my professor prefers I don\'t do it this

Answer 1

Try regular expression

^(?=.*[a-z])(?=.*[A-Z])(?=.*\d).+$

descriptions are as follow
(?=.*[a-z])  -- check lower case letter
(?=.*[A-Z]) -- check upper case letter
(?=.*\d) -- check one digit exists