Regex pattern "^\\|:\\|$" not detecting pipes at beginning and end of string

Question

The following piece of code returns false when I believe it should return true. Can anyone tell me why? It's using java.util.regex.Pattern to parse the regex.

Pattern.compile("^\|:\|$".matcher("|   |").matches();

Answer 1

A \ in a string literal must be escaped as \\.

If you want to match anything in between, use .*, not :.

When you use the matches method in Java, you don't need to add the string boundaries ^ and $ as this function returns true only when it matches the whole string.

You seem to want

Pattern.compile("\\|.*\\|").matcher("| |").matches();