Try to resolve first inside the workspace as a project-relative

location, after that, take the path as is.
Don't ignore the path, as it might not exist yet (e.g. project
output folders).

Author: adangel

net.sourceforge.pmd.eclipse.plugin.test/src/main/java/net/sourceforge/pmd/eclipse/runtime/cmd/ReviewCmdTest.java

@@ -45,9 +45,6 @@
 public class ReviewCmdTest {
     private IProject testProject;
 
-    /**
-     * @see junit.framework.TestCase#setUp()
-     */
     @Before
     public void setUp() throws Exception {
 
@@ -68,9 +65,6 @@ public void setUp() throws Exception {
         properties.setPmdEnabled(true);
     }
 
-    /**
-     * @see junit.framework.TestCase#tearDown()
-     */
     @After
     public void tearDown() throws Exception {
         try {

net.sourceforge.pmd.eclipse.plugin/src/main/java/net/sourceforge/pmd/eclipse/runtime/cmd/JavaProjectClassLoader.java

@@ -132,19 +132,25 @@ private void addURL(IClasspathEntry classpathEntry) {
 
     private void addURL(IPath path) {
         try {
-            File absoluteFile = path.toFile().getAbsoluteFile();
-            // if the file exists, it is already an absolute path
-            if (!absoluteFile.exists()) {
-                // if not, it might have been a workspace relative file reference
-                absoluteFile = workspace.getRoot().getFile(path).getLocation().toFile().getAbsoluteFile();
+            File absoluteFile = null;
+            IPath location = workspace.getRoot().getFile(path).getLocation();
+            if (location != null) {
+                // location is only present, if a project exists in the workspace
+                // in other words: only if path referenced something inside an existing project
+                absoluteFile = location.toFile().getAbsoluteFile();
+            }
+
+            if (absoluteFile == null) {
+                // if location couldn't be resolved, then it is already an absolute path
+                absoluteFile = path.toFile().getAbsoluteFile();
             }
-            if (absoluteFile.exists()) {
-                URL url = absoluteFile.toURI().toURL();
-                LOG.debug("auxclasspath: Adding url {}", url);
-                addURL(url);
-            } else {
-                LOG.warn("auxclasspath: Resolved file {} does not exist and is ignored", absoluteFile);
+
+            if (!absoluteFile.exists()) {
+                LOG.warn("auxclasspath: Resolved file {} does not exist", absoluteFile);
             }
+            URL url = absoluteFile.toURI().toURL();
+            LOG.debug("auxclasspath: Adding url {}", url);
+            addURL(url);
         } catch (MalformedURLException e) {
             LOG.warn("MalformedURLException occurred: {}", e.getMessage(), e);
         }