Java interprets backslashes that are used as string literals as Unicode or character escapes. To prevent the Java byte code compiler from interpreting them, use a double backslash in string literals that use regular expressions.

For example, the string literal

\b

matches a single backspace character when interpreted as a regular expression. However,

\\b

matches a word boundary. The string literal

\(hello\)

is illegal and results in a compile-time error. To match the string "(hello)," use the string literal

\\(hello\\)

.