Regex for checking if a string is strictly alphanumeric

Question

How can I check if a string contains only numbers and alphabets ie. is alphanumeric?

Answer 1

See the documentation of Pattern.

Assuming US-ASCII alphabet (a-z, A-Z), you could use \p{Alnum}.

A regex to check that a line contains only such characters is "^[\\p{Alnum}]*$".

That also matches empty string. To exclude empty string: "^[\\p{Alnum}]+$".