Java JAR files locked by ClassLoader

Question

I am extracting a WAR in a temporary folder and adding all the classes and libs to a URLClassLoader .

When I start to load the classes into the classpath, the JAR files under "WEB-INF/lib/" are locked by the JVM.

After doing the job, I close the classpath, call the GC and delete the temporary directory.

When I am deleting the temporary directory, I can delete all the files except the JAR files under "WEB-INF/lib".

My code:

@Override
public void generateRegressionTestClasses(Path fileJARorWarSolution, List<String> canonicalNameClassesToGenerateTests) throws Exception {

    Path tempPath = null;
    URLClassLoader classLoader = null;
    TryTest tryTest = null;
    RDP execution = null;
    try {
        // This extracts the JAR/WAR and prepares the URLClassLoader.
        GenFilterResponse response = genFilterClass.runGenFilterClass(path);

        classLoader = response.getCl();
        tempPath = response.getTempPath();

        // Verify that all the Test classes is in the ClassLoader.
        // Here is where the JAR files are locked.
        for (String s : canonicalNameClassesToGenerateTests) {
            try {
                classLoader.loadClass(s);
            } catch (ClassNotFoundException e) {
                throw new CustomException(CustomTexts.ERROR_CLASS_NOT_LOADED + s);
            }
        }

        execution = new RDP();
        execution.setClassLoader(classLoader);

        TryTest = new TryTest(execution);
        tryTest.handle(null);
    } finally {
        tryTest = null;
        execution = null;
        if (classLoader != null) {
            try {
                classLoader.close();
            } catch (Exception e) {
                //
            } finally {
                classLoader = null;
                System.gc();
            }
        }
        if (tempPath != null) {
            FileSystemUtils.deleteRecursively(tempPath.toFile());
        }
    }

Anybody knows how to unlock these files?

Answer 1

Solved.

If I load the JAR into the Class Loader with this kind of URI:

new URL("jar:file:" + jar.toAbsolutePath().toString() + "!/").toURI().toURL()

Example URI:

jar:file:c:/myJar.jar

The file is locked after ClassLoader is closed.

If I load the JAR into the Class Loader with this kind of URI:

warDirectory.toFile().toURI().toURL()

Example URI:

file:c:/myJar.jar

I can delete the JAR's when the Classloader is closed.