Bug 495333 - ContextFinder returns null from getResourcesR4_6I20160606-1100I20160603-1000

If there are no classes loaded from bundle class loaders on the
stack then ContextFinder.getResources can return null.
This fix ensures an empty enumeration is returned instead.

Change-Id: I07fe25eeaf8d02ea92cbe130794cdd2a011ae481
Signed-off-by: Thomas Watson <tjwatson@us.ibm.com>

3 files changed, 110 insertions, 5 deletions

diff --git a/bundles/org.eclipse.osgi.tests/src/org/eclipse/osgi/tests/bundles/ClassLoadingBundleTests.java b/bundles/org.eclipse.osgi.tests/src/org/eclipse/osgi/tests/bundles/ClassLoadingBundleTests.java
index b4d6729ee..8f4d2b15b 100644
--- a/bundles/org.eclipse.osgi.tests/src/org/eclipse/osgi/tests/bundles/ClassLoadingBundleTests.java
+++ b/bundles/org.eclipse.osgi.tests/src/org/eclipse/osgi/tests/bundles/ClassLoadingBundleTests.java
@@ -14,7 +14,11 @@ import java.io.*;
 import java.lang.reflect.Method;
 import java.net.*;
 import java.util.*;
-import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.*;
+import javax.jws.WebService;
+import javax.xml.namespace.QName;
+import javax.xml.ws.Endpoint;
+import javax.xml.ws.Service;
 import junit.framework.Test;
 import junit.framework.TestSuite;
 import org.eclipse.osgi.tests.OSGiTestsActivator;
@@ -1672,7 +1676,7 @@ public class ClassLoadingBundleTests extends AbstractBundleTests {
 		ClassLoader contextFinder = getContext().getService(getContext().getServiceReferences(ClassLoader.class, "(equinox.classloader.type=contextClassLoader)").iterator().next());
 		// Using a resource we know is in java 8.
 		String resource = "META-INF/services/javax.print.PrintServiceLookup";
-		URL systemURL = ClassLoader.getSystemClassLoader().getResource("META-INF/services/javax.print.PrintServiceLookup");
+		URL systemURL = ClassLoader.getSystemClassLoader().getResource(resource);
 		assertNotNull("Did not find a parent resource: " + resource, systemURL);
 		//should return the file defined in test bundle.
 		URL url = contextFinder.getResource(resource);
@@ -1684,6 +1688,80 @@ public class ClassLoadingBundleTests extends AbstractBundleTests {
 		assertEquals(url.toExternalForm(), urls.get(0).toExternalForm());
 	}
 
+	@WebService(endpointInterface = "org.eclipse.osgi.tests.bundles.TestService")
+	public static class TestServiceImpl implements TestService {
+
+		@Override
+		public String hello(final String name) {
+			return "Hello " + name;
+		}
+
+	}
+
+	/*
+	 * This test depends on the behavior of the JVM Endpoint implementation to use
+	 * the context class loader to try and find resources using an executor.
+	 * This is important because it causes the thread stack to have NO classes
+	 * loaded by a bundle class loader.  This causes a condition that would
+	 * make ContextFinder.getResources to return null
+	 */
+	public void testContextFinderEmptyGetResources() throws Exception {
+		// get the context finder explicitly to test incase the thread context class loader has changed
+		ClassLoader contextFinder = getContext().getService(getContext().getServiceReferences(ClassLoader.class, "(equinox.classloader.type=contextClassLoader)").iterator().next());
+		ClassLoader previousTCCL = Thread.currentThread().getContextClassLoader();
+		Thread.currentThread().setContextClassLoader(contextFinder);
+		ExecutorService pool = null;
+		try {
+			pool = Executors.newFixedThreadPool(3);
+
+			final String address = "http://localhost:8888/service";
+
+			final WebService annotation = TestService.class.getAnnotation(WebService.class);
+			final String namespaceURI = annotation.serviceName();
+			final String localPart = annotation.targetNamespace();
+			final QName serviceName = new QName(namespaceURI, localPart);
+
+			final TestServiceImpl tsi = new TestServiceImpl();
+			final Endpoint endpoint = Endpoint.create(tsi);
+			final HashMap<String, Object> props = new HashMap<String, Object>();
+			props.put(Endpoint.WSDL_SERVICE, serviceName);
+
+			endpoint.setProperties(props);
+			endpoint.setExecutor(pool);
+			endpoint.publish(address);
+			final URL wsdlURL = new URL(address + "?wsdl");
+			final Service s = Service.create(wsdlURL, serviceName);
+			assertNotNull("Service is null.", s);
+			final TestService port = s.getPort(TestService.class);
+
+			assertEquals("Wrong result.", "Hello World", port.hello("World"));
+		} finally {
+			Thread.currentThread().setContextClassLoader(previousTCCL);
+			if (pool != null) {
+				pool.shutdown();
+			}
+		}
+	}
+
+	public void testBundleClassLoaderEmptyGetResources() throws Exception {
+		final ClassLoader bundleClassLoader = getClass().getClassLoader();
+		// Using a resource we know does not exist
+		final String resource = "META-INF/services/test.does.note.ExistService";
+		doTestEmptyGetResources(bundleClassLoader, resource);
+	}
+
+	private void doTestEmptyGetResources(ClassLoader testClassLoader, String resource) throws Exception {
+		URL systemURL = ClassLoader.getSystemClassLoader().getResource(resource);
+		assertNull("Found a parent resource: " + resource, systemURL);
+		// Should return null resource
+		URL testurl = testClassLoader.getResource(resource);
+		assertNull("Found a resource: " + resource, testurl);
+
+		Enumeration<URL> testResources = testClassLoader.getResources(resource);
+		assertNotNull("null resources from testClassLoader: " + resource, testResources);
+		assertFalse("Resources has elements.", testResources.hasMoreElements());
+	}
+
 	public void testBundleReference01() throws Exception {
 		Bundle test = installer.installBundle("test"); //$NON-NLS-1$
 		Class clazz = test.loadClass("test1.Activator"); //$NON-NLS-1$
diff --git a/bundles/org.eclipse.osgi.tests/src/org/eclipse/osgi/tests/bundles/TestService.java b/bundles/org.eclipse.osgi.tests/src/org/eclipse/osgi/tests/bundles/TestService.java
new file mode 100644
index 000000000..c3d2ea34f
--- /dev/null
+++ b/bundles/org.eclipse.osgi.tests/src/org/eclipse/osgi/tests/bundles/TestService.java
@@ -0,0 +1,18 @@
+/*******************************************************************************
+ * Copyright (c) 2016 IBM Corporation and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *     IBM Corporation - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.osgi.tests.bundles;
+
+import javax.jws.WebService;
+
+@WebService(serviceName = "Foo", targetNamespace = "http://bar")
+public interface TestService {
+	String hello(String name);
+}
diff --git a/bundles/org.eclipse.osgi/container/src/org/eclipse/osgi/internal/loader/BundleLoader.java b/bundles/org.eclipse.osgi/container/src/org/eclipse/osgi/internal/loader/BundleLoader.java
index 5fcfed8d1..2e7f0e319 100644
--- a/bundles/org.eclipse.osgi/container/src/org/eclipse/osgi/internal/loader/BundleLoader.java
+++ b/bundles/org.eclipse.osgi/container/src/org/eclipse/osgi/internal/loader/BundleLoader.java
@@ -64,6 +64,10 @@ public class BundleLoader extends ModuleLoader {
 
 	private static final Pattern PACKAGENAME_FILTER = Pattern.compile("\\(osgi.wiring.package\\s*=\\s*([^)]+)\\)"); //$NON-NLS-1$
 
+	// TODO needed instead of using Collections.emptyEnumertion until we no longer support Java 6
+	@SuppressWarnings("rawtypes")
+	private final static Enumeration EMPTY_ENUMERATION = Collections.enumeration(Collections.emptyList());
+
 	private final ModuleWiring wiring;
 	private final EquinoxContainer container;
 	private final Debug debug;
@@ -627,7 +631,7 @@ public class BundleLoader extends ModuleLoader {
 		if ((name.length() > 1) && (name.charAt(0) == '/')) /* if name has a leading slash */
 			name = name.substring(1); /* remove leading slash before search */
 		String pkgName = getResourcePackageName(name);
-		Enumeration<URL> result = Collections.enumeration(Collections.<URL> emptyList());
+		Enumeration<URL> result = emptyEnumeration();
 		boolean bootDelegation = false;
 		// follow the OSGi delegation model
 		// First check the parent classloader for system resources, if it is a java resource.
@@ -781,9 +785,9 @@ public class BundleLoader extends ModuleLoader {
 
 	public static <E> Enumeration<E> compoundEnumerations(Enumeration<E> list1, Enumeration<E> list2) {
 		if (list2 == null || !list2.hasMoreElements())
-			return list1;
+			return list1 == null ? BundleLoader.<E> emptyEnumeration() : list1;
 		if (list1 == null || !list1.hasMoreElements())
-			return list2;
+			return list2 == null ? BundleLoader.<E> emptyEnumeration() : list2;
 		List<E> compoundResults = new ArrayList<E>();
 		while (list1.hasMoreElements())
 			compoundResults.add(list1.nextElement());
@@ -795,6 +799,11 @@ public class BundleLoader extends ModuleLoader {
 		return Collections.enumeration(compoundResults);
 	}
 
+	@SuppressWarnings("unchecked")
+	private static <E> Enumeration<E> emptyEnumeration() {
+		return EMPTY_ENUMERATION;
+	}
+
 	/**
 	 * Finds a resource local to this bundle.  Only the classloader for this bundle is searched.
 	 * @param name The name of the resource to find.