Error: "The method show() from the type Window is deprecated"

The method show() is, indeed, deprecated. Deprecated means that you're not supposed to use it anymore, as it's been replaced by something better and may be removed in the future. In this case, you're supposed to use setVisible(true) instead.

If you go and look at the Javadoc for a deprecated method, it will generally tell you what the intended replacement is.

You now have to use setVisible(true) instead.