Prepara texto para insertarlo de forma segura en una cadena Java.
Genera la forma escapada que puedes pegar entre comillas en código Java.
Backslash becomes \\, a double quote becomes \", newline \n, carriage return \r, tab \t, backspace \b, form feed \f. Other control characters turn into \uXXXX.
Not inside a double quoted string, only inside a char literal. There is an option if you need it.
Java escapes the backslash in the string first, and the regex engine then reads the result. A pattern for a digit, \d, has to be written "\\d" in the source.
Java does not escape single quotes by default and has no \v or \x escapes, so the output differs for a few characters.
From Java 15 on, text blocks with triple quotes let you paste multi-line text without escaping line breaks and quotes.