IDEs (and obviously DrJava) are programmed to notice readers, writers, etc., which are not closed. If you open a reader pointing to a file and never close it, the file may become inaccessible to other code, we hope temporarily. So they give you a warning, which you can overlook. Try opening and closing a Scanner pointing to System.in and you will find out why you should ignore such warnings whenever System.in System.out and System.err are involved.
expectation is the root of all heartache - shakespeare. tiny ad: