cutover jarhell to parsing classpath all the time

core/src/main/java/org/elasticsearch/bootstrap/JarHell.java

@@ -26,6 +26,7 @@ import org.elasticsearch.common.logging.ESLogger;
 import org.elasticsearch.common.logging.Loggers;
 
 import java.io.IOException;
+import java.net.MalformedURLException;
 import java.net.URL;
 import java.net.URLClassLoader;
 import java.nio.file.FileVisitResult;
@@ -70,21 +71,43 @@ public class JarHell {
     }
 
     /**
-     * Checks the current classloader for duplicate classes
+     * Checks the current classpath for duplicate classes
      * @throws IllegalStateException if jar hell was found
      */
     public static void checkJarHell() throws Exception {
         ClassLoader loader = JarHell.class.getClassLoader();
-        if (loader instanceof URLClassLoader == false) {
-           return;
-        }
         ESLogger logger = Loggers.getLogger(JarHell.class);
         if (logger.isDebugEnabled()) {
             logger.debug("java.class.path: {}", System.getProperty("java.class.path"));
             logger.debug("sun.boot.class.path: {}", System.getProperty("sun.boot.class.path"));
+            if (loader instanceof URLClassLoader ) {
                 logger.debug("classloader urls: {}", Arrays.toString(((URLClassLoader)loader).getURLs()));
              }
-        checkJarHell(((URLClassLoader) loader).getURLs());
+        }
+        checkJarHell(parseClassPath());
+    }
+    
+    /**
+     * Parses the classpath into a set of URLs
+     */
+    @SuppressForbidden(reason = "resolves against CWD because that is how classpaths work")
+    public static URL[] parseClassPath()  {
+        String elements[] = System.getProperty("java.class.path").split(System.getProperty("path.separator"));
+        URL urlElements[] = new URL[elements.length];
+        for (int i = 0; i < elements.length; i++) {
+            String element = elements[i];
+            // empty classpath element behaves like CWD.
+            if (element.isEmpty()) {
+                element = System.getProperty("user.dir");
+            }
+            try {
+                urlElements[i] = PathUtils.get(element).toUri().toURL();
+            } catch (MalformedURLException e) {
+                // should not happen, as we use the filesystem API
+                throw new RuntimeException(e);
+            }
+        }
+        return urlElements;
     }
 
     /**

core/src/main/java/org/elasticsearch/bootstrap/Security.java

@@ -24,7 +24,6 @@ import org.elasticsearch.env.Environment;
 
 import java.io.*;
 import java.net.URL;
-import java.net.URLClassLoader;
 import java.nio.file.AccessMode;
 import java.nio.file.FileAlreadyExistsException;
 import java.nio.file.Files;
@@ -133,9 +132,7 @@ final class Security {
      */
     @SuppressForbidden(reason = "proper use of URL")
     static void setCodebaseProperties() {
-        ClassLoader loader = Security.class.getClassLoader();
+        for (URL url : JarHell.parseClassPath()) {
-        if (loader instanceof URLClassLoader) {
-            for (URL url : ((URLClassLoader)loader).getURLs()) {
             for (Map.Entry<Pattern,String> e : SPECIAL_JARS.entrySet()) {
                 if (e.getKey().matcher(url.getPath()).matches()) {
                     String prop = e.getValue();
@@ -151,10 +148,6 @@ final class Security {
                 System.setProperty(prop, "file:/dev/null"); // no chance to be interpreted as "all"
             }
         }
-        } else {
-            // we could try to parse the classpath or something, but screw it for now.
-            throw new UnsupportedOperationException("Unsupported system classloader type: " + loader.getClass());
-        }
     }
 
     /** returns dynamic Permissions to configured paths */

core/src/main/java/org/elasticsearch/plugins/PluginManager.java

@@ -41,7 +41,6 @@ import java.io.IOException;
 import java.io.OutputStream;
 import java.net.MalformedURLException;
 import java.net.URL;
-import java.net.URLClassLoader;
 import java.nio.file.*;
 import java.nio.file.attribute.BasicFileAttributes;
 import java.nio.file.attribute.PosixFileAttributeView;
@@ -315,10 +314,7 @@ public class PluginManager {
     private void jarHellCheck(Path candidate, boolean isolated) throws IOException {
         // create list of current jars in classpath
         final List<URL> jars = new ArrayList<>();
-        ClassLoader loader = PluginManager.class.getClassLoader();
+        jars.addAll(Arrays.asList(JarHell.parseClassPath()));
-        if (loader instanceof URLClassLoader) {
-            Collections.addAll(jars, ((URLClassLoader) loader).getURLs());
-        }
 
         // read existing bundles. this does some checks on the installation too.
         List<Bundle> bundles = PluginsService.getPluginBundles(environment.pluginsFile());

core/src/main/java/org/elasticsearch/plugins/PluginsService.java

@@ -47,6 +47,7 @@ import java.nio.file.DirectoryStream;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
@@ -331,12 +332,7 @@ public class PluginsService extends AbstractComponent {
             // pluginmanager does it, but we do it again, in case lusers mess with jar files manually
             try {
                 final List<URL> jars = new ArrayList<>();
-                ClassLoader parentLoader = getClass().getClassLoader();
+                jars.addAll(Arrays.asList(JarHell.parseClassPath()));
-                if (parentLoader instanceof URLClassLoader) {
-                    for (URL url : ((URLClassLoader) parentLoader).getURLs()) {
-                        jars.add(url);
-                    }
-                }
                 jars.addAll(bundle.urls);
                 JarHell.checkJarHell(jars.toArray(new URL[0]));
             } catch (Exception e) {

core/src/test/java/org/elasticsearch/bootstrap/BootstrapForTesting.java

@@ -86,7 +86,7 @@ public class BootstrapForTesting {
                 // initialize paths the same exact way as bootstrap.
                 Permissions perms = new Permissions();
                 // add permissions to everything in classpath
-                for (URL url : ((URLClassLoader)BootstrapForTesting.class.getClassLoader()).getURLs()) {
+                for (URL url : JarHell.parseClassPath()) {
                     Path path = PathUtils.get(url.toURI());
                     // resource itself
                     perms.add(new FilePermission(path.toString(), "read,readlink"));