String.replace(char, char) method - not changing string permanently

[James Brooks]

Hi guys,

I take it the String.replace(char, char) method not not change the string permanently? I mean, if I run the below program, what prints out on the command line is the muted string, but what appears in the JOptionPane after the replace() command is used is the original string, not modified. How can I change the string? Only by assigning it a new value completely?

Thanks!
-Patrick

import javax.swing.JOptionPane;
public class Chapter7Strings
{
    public static void main(String[] args)
    {
        
      String myString = "Here is my extremely complex, long-winded string";
      JOptionPane.showMessageDialog(null, "The first appearance of the letter 'x' is at position " +
              myString.indexOf('x'));
      JOptionPane.showMessageDialog(null, "The letter at position 13 is " + myString.charAt(12));
      JOptionPane.showMessageDialog(null, "The value of ends with g is " + myString.endsWith("g"));
      System.out.println(myString.replace('x', 'n'));
      JOptionPane.showMessageDialog(null, "After replacing 'x' with 'n', the string is: " + myString);
    }
}

[Paul Clapham]

Not only does it not change the string permanently, it doesn't change the string at all. The documentation is quite clear about this, it says about that method

Returns a new string resulting from replacing all occurrences of oldChar in this string with newChar.

In fact there are no methods that change a string in any way.

You can of course assign a new string to a variable, which I think is what you want to do. But that doesn't constitute changing a string, it only assigns a different string to the variable and leaves the original string unchanged.
[ April 11, 2007: Message edited by: Paul Clapham ]

[James Brooks]

Thanks, Paul, if it returns a string I know how to use it. So, strings really are immutable, after all...

-Patrick