Do action when something is printed in System.err

Question

Like in topic - I am trying to do action when anything is printed into error stream, but code below is not working:

try {
    System.setOut(new PrintStream("InfoLog.txt"));
    System.setErr(new PrintStream(new FileOutputStream("ErrorLog.txt") {
        public void write(int b) throws IOException {
            super.write(b);
            error();
        }
        public void write(byte[] b) throws IOException {
            super.write(b);
            error();
        }
    }));
} catch (FileNotFoundException ex) {
    Logger.getLogger(HouseCalc.class.getName()).log(Level.SEVERE, null, ex);
}

Is there any way to "catch" the System.err stream and make any action before it gets printed to file?

Answer 1

Make sure to override the appropriate methods . Have a good look at the source of PrintStream , because they might be calling each other . You want to get all the way down.

write(char cbuf[], int off, int len)

might be the one you really need.