Name: krT82822 Date: 01/29/2000


WClipboard.setClipboardText() has a memory leak. This exists in the 1.1 JDK's and 1.2.2,
but appears to have been fixed in 1.3 (though I can't find a bug number for it). Should be
an easy fix for 1.1.9.
Basically, the native code for this method in awt_clipboard.cpp creates a temporary string
to hold the text, but never frees it. For large strings this can be a massive memory leak.
A simple test case to illustrate the problem follows. If you run this, you will see the memory
usage skyrocket. Warning: running this test case will quickly blow out your system's virtual
memory and could cause things to crash:

import java.awt.datatransfer.Clipboard;
import java.awt.datatransfer.ClipboardOwner;
import java.awt.datatransfer.StringSelection;
import java.awt.datatransfer.Transferable;
import java.awt.Toolkit;
public class CBTest implements ClipboardOwner {
    public static void main(String[] args) {
        new CBTest();
    }
    public CBTest() {
        // Get System Clipboard
        Clipboard sysCB =
            Toolkit.getDefaultToolkit().getSystemClipboard();
        // Create a very long string
        String str = "";
        for (int i = 0; i < 100; i++) {
        str += "This is a very long string to illustrate the leak";
        }
        // Put the string on the clipboard
        StringSelection sel = new StringSelection(str);
        while (true) {
            sysCB.setContents(sel, this);
        }
    }
    public void lostOwnership(Clipboard clipboard,
                              Transferable contents) {
    }
}

The fix is very easy, simply add the statement "delete[] ucText;" to the end of the function.
Though this may seem like a minor leak, we have some products that use the clipboard for
transfering database information to other applications, like spreadsheets. This data can be
very large.
(Review ID: 100372)
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