How do I redirect output of Getopt error message to a string?

Question

I need to store Getopt class error message to a string.

Normally that error will be printed in standard error console.

How would I do this?

Do you mean an **exception**? [This might help](http://stackoverflow.com/questions/1149703/stacktrace-to-string-in-java). However, we wouldn't have to guess if you showed us your code, and your exact requirements, and what the code does instead... — ppeterka, Sep 26 '13 at 08:34

score 1 · Accepted Answer · answered Sep 26 '13 at 08:52

You may be able to use System.setOut and/or System.setErr.

As an example:

static void printMessage()
{
  System.out.println("Hello");
}

public static void main(String[] args) throws Exception
{
  // ByteArrayOutputStream = in-memory output stream
  OutputStream output = new ByteArrayOutputStream();
  PrintStream oldStream = System.out; // store the current output stream
  System.setOut(new PrintStream(output)); // change the output stream
  printMessage(); // call function that prints to System.out
  System.setOut(oldStream); // restore the old output stream
  System.out.println("Output from stream: " + output.toString());
}

The above will lead to only the following output:

Output from stream: Hello

How do I redirect output of Getopt error message to a string?

1 Answers1