@SuppressWarnings("unchecked")
private final <T> T[] copy(T[] source) {
   Class type = source.getClass().getComponentType();
   T[] target = (T[])Array.newInstance(type, source.length);
   System.arraycopy(source, 0, target, 0, source.length);
   return target;
}

JDK6부터는 Arrays.copyOf가 위의 메소드를 대신 하게 되었다. 

톰캣 정신은 코드 유지보수성과 세련미가 우선이지. 민감한 성능차이는 아닌듯 싶다..

--- tomcat/tc6.0.x/trunk/java/org/apache/catalina/loader/ResourceEntry.java	2010/05/06 19:15:48	941867
+++ tomcat/tc6.0.x/trunk/java/org/apache/catalina/loader/ResourceEntry.java	2010/05/06 19:17:49	941868
@@ -47,7 +47,7 @@
     /**
      * Loaded class.
      */
-    public Class loadedClass = null;
+    public volatile Class loadedClass = null;
 
 
     /**

--- tomcat/tc6.0.x/trunk/java/org/apache/catalina/loader/WebappClassLoader.java	2010/05/06 19:15:48	941867
+++ tomcat/tc6.0.x/trunk/java/org/apache/catalina/loader/WebappClassLoader.java	2010/05/06 19:17:49	941868
@@ -1432,102 +1432,121 @@
      *
      * @exception ClassNotFoundException if the class was not found
      */
-    public Class loadClass(String name, boolean resolve)
+    public synchronized Class loadClass(String name, boolean resolve)
         throws ClassNotFoundException {
 
-        synchronized (name.intern()) {
-            if (log.isDebugEnabled())
-                log.debug("loadClass(" + name + ", " + resolve + ")");
-            Class clazz = null;
-    
-            // Log access to stopped classloader
-            if (!started) {
-                try {
-                    throw new IllegalStateException();
-                } catch (IllegalStateException e) {
-                    log.info(sm.getString("webappClassLoader.stopped", name), e);
-                }
+        if (log.isDebugEnabled())
+            log.debug("loadClass(" + name + ", " + resolve + ")");
+        Class clazz = null;
+
+        // Log access to stopped classloader
+        if (!started) {
+            try {
+                throw new IllegalStateException();
+            } catch (IllegalStateException e) {
+                log.info(sm.getString("webappClassLoader.stopped", name), e);
             }
-    
-            // (0) Check our previously loaded local class cache
-            clazz = findLoadedClass0(name);
+        }
+
+        // (0) Check our previously loaded local class cache
+        clazz = findLoadedClass0(name);
+        if (clazz != null) {
+            if (log.isDebugEnabled())
+                log.debug("  Returning class from cache");
+            if (resolve)
+                resolveClass(clazz);
+            return (clazz);
+        }
+
+        // (0.1) Check our previously loaded class cache
+        clazz = findLoadedClass(name);
+        if (clazz != null) {
+            if (log.isDebugEnabled())
+                log.debug("  Returning class from cache");
+            if (resolve)
+                resolveClass(clazz);
+            return (clazz);
+        }
+
+        // (0.2) Try loading the class with the system class loader, to prevent
+        //       the webapp from overriding J2SE classes
+        try {
+            clazz = system.loadClass(name);
             if (clazz != null) {
-                if (log.isDebugEnabled())
-                    log.debug("  Returning class from cache");
                 if (resolve)
                     resolveClass(clazz);
                 return (clazz);
             }
-    
-            // (0.1) Check our previously loaded class cache
-            clazz = findLoadedClass(name);
-            if (clazz != null) {
-                if (log.isDebugEnabled())
-                    log.debug("  Returning class from cache");
-                if (resolve)
-                    resolveClass(clazz);
-                return (clazz);
+        } catch (ClassNotFoundException e) {
+            // Ignore
+        }
+
+        // (0.5) Permission to access this class when using a SecurityManager
+        if (securityManager != null) {
+            int i = name.lastIndexOf('.');
+            if (i >= 0) {
+                try {
+                    securityManager.checkPackageAccess(name.substring(0,i));
+                } catch (SecurityException se) {
+                    String error = "Security Violation, attempt to use " +
+                        "Restricted Class: " + name;
+                    log.info(error, se);
+                    throw new ClassNotFoundException(error, se);
+                }
             }
-    
-            // (0.2) Try loading the class with the system class loader, to prevent
-            //       the webapp from overriding J2SE classes
+        }
+
+        boolean delegateLoad = delegate || filter(name);
+
+        // (1) Delegate to our parent if requested
+        if (delegateLoad) {
+            if (log.isDebugEnabled())
+                log.debug("  Delegating to parent classloader1 " + parent);
+            ClassLoader loader = parent;
+            if (loader == null)
+                loader = system;
             try {
-                clazz = system.loadClass(name);
+                clazz = loader.loadClass(name);
                 if (clazz != null) {
+                    if (log.isDebugEnabled())
+                        log.debug("  Loading class from parent");
                     if (resolve)
                         resolveClass(clazz);
                     return (clazz);
                 }
             } catch (ClassNotFoundException e) {
-                // Ignore
-            }
-    
-            // (0.5) Permission to access this class when using a SecurityManager
-            if (securityManager != null) {
-                int i = name.lastIndexOf('.');
-                if (i >= 0) {
-                    try {
-                        securityManager.checkPackageAccess(name.substring(0,i));
-                    } catch (SecurityException se) {
-                        String error = "Security Violation, attempt to use " +
-                            "Restricted Class: " + name;
-                        log.info(error, se);
-                        throw new ClassNotFoundException(error, se);
-                    }
-                }
+                ;
             }
-    
-            boolean delegateLoad = delegate || filter(name);
-    
-            // (1) Delegate to our parent if requested
-            if (delegateLoad) {
+        }
+
+        // (2) Search local repositories
+        if (log.isDebugEnabled())
+            log.debug("  Searching local repositories");
+        try {
+            clazz = findClass(name);
+            if (clazz != null) {
                 if (log.isDebugEnabled())
-                    log.debug("  Delegating to parent classloader1 " + parent);
-                ClassLoader loader = parent;
-                if (loader == null)
-                    loader = system;
-                try {
-                    clazz = loader.loadClass(name);
-                    if (clazz != null) {
-                        if (log.isDebugEnabled())
-                            log.debug("  Loading class from parent");
-                        if (resolve)
-                            resolveClass(clazz);
-                        return (clazz);
-                    }
-                } catch (ClassNotFoundException e) {
-                    ;
-                }
+                    log.debug("  Loading class from local repository");
+                if (resolve)
+                    resolveClass(clazz);
+                return (clazz);
             }
-    
-            // (2) Search local repositories
+        } catch (ClassNotFoundException e) {
+            ;
+        }
+
+        // (3) Delegate to parent unconditionally
+        if (!delegateLoad) {
             if (log.isDebugEnabled())
-                log.debug("  Searching local repositories");
+                log.debug("  Delegating to parent classloader at end: " + parent);
+            ClassLoader loader = parent;
+            if (loader == null)
+                loader = system;
             try {
-                clazz = findClass(name);
+                clazz = loader.loadClass(name);
                 if (clazz != null) {
                     if (log.isDebugEnabled())
-                        log.debug("  Loading class from local repository");
+                        log.debug("  Loading class from parent");
                     if (resolve)
                         resolveClass(clazz);
                     return (clazz);
@@ -1535,30 +1554,10 @@
             } catch (ClassNotFoundException e) {
                 ;
             }
-    
-            // (3) Delegate to parent unconditionally
-            if (!delegateLoad) {
-                if (log.isDebugEnabled())
-                    log.debug("  Delegating to parent classloader at end: " + parent);
-                ClassLoader loader = parent;
-                if (loader == null)
-                    loader = system;
-                try {
-                    clazz = loader.loadClass(name);
-                    if (clazz != null) {
-                        if (log.isDebugEnabled())
-                            log.debug("  Loading class from parent");
-                        if (resolve)
-                            resolveClass(clazz);
-                        return (clazz);
-                    }
-                } catch (ClassNotFoundException e) {
-                    ;
-                }
-            }
-    
-            throw new ClassNotFoundException(name);
         }
+
+        throw new ClassNotFoundException(name);
+
     }
 
 
@@ -2544,7 +2543,7 @@
         if (clazz != null)
             return clazz;
 
-        synchronized (name.intern()) {
+        synchronized (this) {
             clazz = entry.loadedClass;
             if (clazz != null)
                 return clazz;

--- tomcat/tc6.0.x/trunk/java/org/apache/jasper/servlet/JasperLoader.java	2010/05/06 19:15:48	941867
+++ tomcat/tc6.0.x/trunk/java/org/apache/jasper/servlet/JasperLoader.java	2010/05/06 19:17:49	941868
@@ -91,7 +91,7 @@
      *                                     
      * @exception ClassNotFoundException if the class was not found
      */                                    
-    public Class loadClass(final String name, boolean resolve)
+    public synchronized Class loadClass(final String name, boolean resolve)
         throws ClassNotFoundException {
 
         Class clazz = null;                
@@ -169,4 +169,4 @@
     public final PermissionCollection getPermissions(CodeSource codeSource) {
         return permissionCollection;
     }
-}
\ No newline at end of file
+}