diff --git a/springloaded/src/main/java/org/springsource/loaded/TypeRegistry.java b/springloaded/src/main/java/org/springsource/loaded/TypeRegistry.java
index 83621ea..39eea2d 100644
--- a/springloaded/src/main/java/org/springsource/loaded/TypeRegistry.java
+++ b/springloaded/src/main/java/org/springsource/loaded/TypeRegistry.java
@@ -1125,10 +1125,13 @@ public class TypeRegistry {
 		if (typeId >= reloadableTypes.length) {
 			resizeReloadableTypeArray(typeId);
 		}
-		reloadableTypes[typeId] = rtype;
-		if ((typeId + 1) > reloadableTypesSize) {
-			reloadableTypesSize = typeId + 1;
+		synchronized(this) {
+			reloadableTypes[typeId] = rtype;
+			if ((typeId + 1) > reloadableTypesSize) {
+				reloadableTypesSize = typeId + 1;
+			}
 		}
+
 		// allocatedIds.put(slashname, rtype);
 		// allocatedButNotYetRegisteredItds.remove(slashname);
 		int cglibIndex = slashname.indexOf("$$EnhancerBy");
@@ -1196,10 +1199,13 @@ public class TypeRegistry {
 		if (typeId >= reloadableTypes.length) {
 			resizeReloadableTypeArray(typeId);
 		}
-		reloadableTypes[typeId] = rtype;
-		if ((typeId + 1) > reloadableTypesSize) {
-			reloadableTypesSize = typeId + 1;
+		synchronized(this) {
+			reloadableTypes[typeId] = rtype;
+			if ((typeId + 1) > reloadableTypesSize) {
+				reloadableTypesSize = typeId + 1;
+			}
 		}
+
 	}
 
 	/**
diff --git a/springloaded/src/main/java/org/springsource/loaded/agent/FileSystemWatcherInterface.java b/springloaded/src/main/java/org/springsource/loaded/agent/FileSystemWatcherInterface.java
new file mode 100644
index 0000000..225c729
--- /dev/null
+++ b/springloaded/src/main/java/org/springsource/loaded/agent/FileSystemWatcherInterface.java
@@ -0,0 +1,18 @@
+package org.springsource.loaded.agent;
+
+import java.io.File;
+
+public interface AbstractFileSystemWatcher {
+	/**
+	 * Shutdown the thread.
+	 */
+	public void shutdown();
+
+	/**
+	 * Add a new file to the list of those being monitored. If the file is something that can be watched, then this
+	 * method will cause the thread to start (if it hasn't already been started).
+	 *
+	 * @param fileToMonitor the file to start monitor
+	 */
+	public void register(File fileToMonitor);
+}
diff --git a/springloaded/src/main/java/org/springsource/loaded/agent/MacOsFileSystemWatcher.java b/springloaded/src/main/java/org/springsource/loaded/agent/MacOsFileSystemWatcher.java
new file mode 100644
index 0000000..476b38b
--- /dev/null
+++ b/springloaded/src/main/java/org/springsource/loaded/agent/MacOsFileSystemWatcher.java
@@ -0,0 +1,4 @@
+package org.springsource.loaded.agent;
+
+public class MacOsFileSystemWatcher {
+}
diff --git a/springloaded/src/main/java/org/springsource/loaded/agent/PollingFileSystemWatcher.java b/springloaded/src/main/java/org/springsource/loaded/agent/PollingFileSystemWatcher.java
new file mode 100644
index 0000000..f3e69fc
--- /dev/null
+++ b/springloaded/src/main/java/org/springsource/loaded/agent/PollingFileSystemWatcher.java
@@ -0,0 +1,4 @@
+package org.springsource.loaded.agent;
+
+public class PollingFileSystemWatcher {
+}
diff --git a/springloaded/src/test/java/org/springsource/loaded/test/FileSystemWatcherTests.java b/springloaded/src/test/java/org/springsource/loaded/test/PollingFileSystemWatcherTests.java
similarity index 100%
rename from springloaded/src/test/java/org/springsource/loaded/test/FileSystemWatcherTests.java
rename to springloaded/src/test/java/org/springsource/loaded/test/PollingFileSystemWatcherTests.java