Replace in backslash "\" in java

The first parameter of the replaceAll method is a regular expression. So there are two alternatives:

• Use the correct regular expression. With "\\" in the source code, each \ is an escape sequence for the \ character, so that the content of the string that the compiler will see will be \ . As a regular expression, this is the escape sequence for the character \ alone.

• Do not use regular expressions and use the method replace instead of replaceAll .

Here's a test that uses both approaches:

class Teste {
    public static void main(String[] args) {
        String teste1 = "a\b\c\d\e";
        System.out.println(teste1);
        String teste2 = teste1.replace("\", "");
        System.out.println(teste2);
        String teste3 = teste1.replaceAll("\\", "");
        System.out.println(teste3);
    }
}

Your output is this:

a\b\c\d\e
abcde
abcde

See here working on ideone.

Oh, and remember that strings are immutable, so if you do this:

String pesquisa = "\uma\string\cheia\de\barras\invertidas\";
f = new File(path,prefix + "_" + dataArq + "_" + pesquisa.replaceAll("\\", "") + ".txt");
System.out.println(pesquisa);

The original string full of backslashes is what will appear in System.out.println . On the other hand, if you do this:

String pesquisa = "\uma\string\cheia\de\barras\invertidas\";
String pesquisa2 = pesquisa.replaceAll("\\", ""); // Ou .replace("\", "");
f = new File(path,prefix + "_" + dataArq + "_" + pesquisa2 + ".txt");
System.out.println(pesquisa2); // É "pesquisa2"! Não é "pesquisa"!

There you will print the result without the backslashes.