URLClassLoader:addURL RI behavior inconsistent with a spec in case duplicate URLs.

Spec says:

=======spec========
addURL

protected void addURL(URL url)

    Appends the specified URL to the list of URLs to search for classes and resources.

    Parameters:
        url - the URL to be added to the search path of URLs
=====================

But if url already in the list of URLs it will not be appended.
This is so for the latest versions of java6 and java5.

We cannot add URL which already in the list of URLs. However we CAN add duplicate urls providing them at the construction time. But whats the difference if url added in the construction time or later using addURL? Spec says that URL will be appended in any way, so RI should be fixed. However, may be the problem with a spec and spec should say something like "Appends the specified URL to the list of URLs to search for classes and resources, if this URL is not already in the list"


The following sample illustrates the problem. Sample output follows the code.

=========AddURLBug.java======================
import java.net.URL;
import java.net.MalformedURLException;
import java.net.URLClassLoader;
import java.util.Arrays;


public class AddURLBug {

private URL url = null;

private void init()throws MalformedURLException {
url = new URL("file:///C:/somedir/");
}

private void printDebugInformation(URL initialURLs[], URL addedURLs[], URL result[]) {
System.out.println("INITIAL URLS:");
for(int i=0; i<initialURLs.length; i++) {
System.out.println("initialURLs["+i+"] " + initialURLs[i]);
}
System.out.println("ADDED URLS:");
for(int i=0; i<addedURLs.length; i++) {
System.out.println("addedURLs["+i+"] " + addedURLs[i]);
}
System.out.println("RESULT URLS:");
for(int i=0; i<result.length; i++) {
System.out.println("result["+i+"] " + result[i]);
}
}

private boolean additionSucceed(Object[] initial, Object[] added, Object[] expected) {
Object[] result = new Object[initial.length + added.length];
System.arraycopy(initial, 0, result, 0, initial.length);
System.arraycopy(added, 0, result, initial.length, added.length);
return Arrays.equals(expected, result);
}

private void addURLs(TestURLClassLoader ucl, URL[] addedURLs) {
for (int i=0; i<addedURLs.length; i++) {
ucl.addURLCall(addedURLs[i]);
}
}

private void checkAddURLs(URL[] initial, URL[] added) throws SecurityException {
TestURLClassLoader ucl = null;

ucl = new TestURLClassLoader(initial);

addURLs(ucl, added);
URL[] resArrayOfURLs = ucl.getURLs();

if (!additionSucceed(initial, added, resArrayOfURLs)) {
System.out.println("FAILED");
printDebugInformation(initial, added, resArrayOfURLs);
} else {
System.out.println("PASSED");
printDebugInformation(initial, added, resArrayOfURLs);
}
}

public static void main(String[] args) throws Exception {
new AddURLBug().run();
}


public void run() throws MalformedURLException {
init();
URL[] initialURLs = new URL[] {};
URL[] addedURLs = new URL[] {url, url, url};
checkAddURLs(initialURLs, addedURLs);
}

private class TestURLClassLoader extends URLClassLoader {

public TestURLClassLoader(URL[] urls) {
super(urls);
}

public TestURLClassLoader(URL[] urls, ClassLoader parent) {
super(urls, parent);
}

public void addURLCall(URL url) {
super.addURL(url);
}
}

}
========Output1 (build 1.6.0-rc-b95)=========
FAILED
INITIAL URLS:
ADDED URLS:
addedURLs[0] file:/C:/somedir/
addedURLs[1] file:/C:/somedir/
addedURLs[2] file:/C:/somedir/
RESULT URLS:
result[0] file:/C:/somedir/

========Output2 (build 1.5.0_09-ea-b01)========
FAILED
INITIAL URLS:
ADDED URLS:
addedURLs[0] file:/C:/somedir/
addedURLs[1] file:/C:/somedir/
addedURLs[2] file:/C:/somedir/
RESULT URLS:
result[0] file:/C:/somedir/

========Output3 (build 1.5.0-b64)========
PASSED
INITIAL URLS:
ADDED URLS:
addedURLs[0] file:/C:/somedir/
addedURLs[1] file:/C:/somedir/
addedURLs[2] file:/C:/somedir/
RESULT URLS:
result[0] file:/C:/somedir/
result[1] file:/C:/somedir/
result[2] file:/C:/somedir/

========Output4 (build 1.4.2-rc-b25)========
PASSED
INITIAL URLS:
ADDED URLS:
addedURLs[0] file:/C:/somedir/
addedURLs[1] file:/C:/somedir/
addedURLs[2] file:/C:/somedir/
RESULT URLS:
result[0] file:/C:/somedir/
result[1] file:/C:/somedir/
result[2] file:/C:/somedir/

========Output4 (build 1.4.2_11-b06)========
FAILED
INITIAL URLS:
ADDED URLS:
addedURLs[0] file:/C:/somedir/
addedURLs[1] file:/C:/somedir/
addedURLs[2] file:/C:/somedir/
RESULT URLS:
result[0] file:/C:/somedir/