Add SystemPropertyUtil.refresh() / Remove DebugUtilTest

- DebugUtilTest does not pass at all unless a new VM is not launched for
  every test method

src/main/java/org/jboss/netty/util/internal/SystemPropertyUtil.java

@@ -25,25 +25,34 @@ import org.jboss.netty.logging.InternalLoggerFactory;
  */
 public final class SystemPropertyUtil {
 
-    private static final InternalLogger logger =
-            InternalLoggerFactory.getInstance(SystemPropertyUtil.class);
-
-    private static final Properties props;
+    private static final Properties props = new Properties();
+    private static final InternalLogger logger;
 
     // Retrieve all system properties at once so that there's no need to deal with
     // security exceptions from next time.  Otherwise, we might end up with logging every
     // security exceptions on every system property access or introducing more complexity
     // just because of less verbose logging.
     static {
+        refresh();
+        logger = InternalLoggerFactory.getInstance(SystemPropertyUtil.class);
+    }
+
+    /**
+     * Re-retrieves all system properties so that any post-launch properties updates are retrieved.
+     */
+    public static void refresh() {
         Properties newProps = null;
         try {
             newProps = System.getProperties();
         } catch (SecurityException e) {
-            logger.warn("Unable to access the system properties; default values will be used.", e);
+            logger.warn("Unable to retrieve the system properties; default values will be used.", e);
             newProps = new Properties();
         }
 
-        props = newProps;
+        synchronized (props) {
+            props.clear();
+            props.putAll(newProps);
+        }
     }
 
     /**

src/test/java/org/jboss/netty/util/DebugUtilTest.java

@@ -1,75 +0,0 @@
-/*
- * Copyright 2012 The Netty Project
- *
- * The Netty Project licenses this file to you under the Apache License,
- * version 2.0 (the "License"); you may not use this file except in compliance
- * with the License. You may obtain a copy of the License at:
- *
- *   http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
- * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
- * License for the specific language governing permissions and limitations
- * under the License.
- */
-package org.jboss.netty.util;
-
-import static org.junit.Assert.*;
-
-import java.security.Permission;
-
-import org.junit.After;
-import org.junit.Before;
-import org.junit.Test;
-
-public class DebugUtilTest {
-
-    public void shouldReturnFalseIfPropertyIsNotSet() {
-        assertFalse(DebugUtil.isDebugEnabled());
-    }
-
-    @Test
-    public void shouldReturnTrueInDebugMode() {
-        System.setProperty("org.jboss.netty.debug", "true");
-        assertTrue(DebugUtil.isDebugEnabled());
-    }
-
-    @Test
-    public void shouldReturnFalseInNonDebugMode() {
-        System.setProperty("org.jboss.netty.debug", "false");
-        assertFalse(DebugUtil.isDebugEnabled());
-    }
-
-    @Test
-    public void shouldNotBombOutWhenSecurityManagerIsInAction() {
-        System.setProperty("org.jboss.netty.debug", "true");
-        System.setSecurityManager(new SecurityManager() {
-            @Override
-            public void checkPropertyAccess(String key) {
-                throw new SecurityException();
-            }
-
-            @Override
-            public void checkPermission(Permission perm, Object context) {
-                // Allow
-            }
-
-            @Override
-            public void checkPermission(Permission perm) {
-                // Allow
-            }
-
-        });
-        try {
-            assertFalse(DebugUtil.isDebugEnabled());
-        } finally {
-            System.setSecurityManager(null);
-        }
-    }
-
-    @Before @After
-    public void cleanup() {
-        System.clearProperty("org.jboss.netty.debug");
-    }
-}