diff --git a/bundles/org.eclipse.osgi/defaultAdaptor/src/org/eclipse/osgi/internal/baseadaptor/BaseClassLoadingHook.java b/bundles/org.eclipse.osgi/defaultAdaptor/src/org/eclipse/osgi/internal/baseadaptor/BaseClassLoadingHook.java
index 8431ac3..f5ffe0b 100644
--- a/bundles/org.eclipse.osgi/defaultAdaptor/src/org/eclipse/osgi/internal/baseadaptor/BaseClassLoadingHook.java
+++ b/bundles/org.eclipse.osgi/defaultAdaptor/src/org/eclipse/osgi/internal/baseadaptor/BaseClassLoadingHook.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2005, 2010 IBM Corporation and others.
+ * Copyright (c) 2005, 2012 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -29,13 +29,21 @@
 	private static final String[] LIB_EXTENSIONS;
 	private static final String[] EMPTY_STRINGS = new String[0];
 	static {
-		String[] libExtensions = ManifestElement.getArrayFromList(FrameworkProperties.getProperty("osgi.framework.library.extensions", FrameworkProperties.getProperty(Constants.FRAMEWORK_LIBRARY_EXTENSIONS)), ","); //$NON-NLS-1$ //$NON-NLS-2$
+		String[] libExtensions = ManifestElement.getArrayFromList(FrameworkProperties.getProperty("osgi.framework.library.extensions", FrameworkProperties.getProperty(Constants.FRAMEWORK_LIBRARY_EXTENSIONS, getOSLibraryExtDefaults())), ","); //$NON-NLS-1$ //$NON-NLS-2$
 		for (int i = 0; i < libExtensions.length; i++)
 			if (libExtensions[i].length() > 0 && libExtensions[i].charAt(0) != '.')
 				libExtensions[i] = '.' + libExtensions[i];
 		LIB_EXTENSIONS = libExtensions;
 	}
 
+	private static String getOSLibraryExtDefaults() {
+		// Some OSes have multiple library extensions
+		// We should provide defaults to the known ones
+		// For example Mac OS X uses dylib and jnilib (bug 380350)
+		String os = FrameworkProperties.getProperty("os.name"); //$NON-NLS-1$
+		return os == null || !os.startsWith("Mac OS") ? null : "dylib,jnilib"; //$NON-NLS-1$ //$NON-NLS-2$
+	}
+
 	/*
 	 * Maps an already mapped library name to additional library file extensions.
 	 * This is needed on platforms like AIX where .a and .so can be used as library file