Bug 552573 - Null check needed in case of connect bundles

Connect bundles have no source base file.  This results in null returned
by getBaseFile.  Other calls to this method were already fixed.  Adding
the null check to DevClassLoadingHook to be safe.

Change-Id: I81e8bdf6c6e00ac95c87f13e560d00364c3a7ae2
Signed-off-by: Thomas Watson <tjwatson@us.ibm.com>
diff --git a/bundles/org.eclipse.osgi/container/src/org/eclipse/osgi/internal/hooks/DevClassLoadingHook.java b/bundles/org.eclipse.osgi/container/src/org/eclipse/osgi/internal/hooks/DevClassLoadingHook.java
index d7ec50b..ca9a3e6 100644
--- a/bundles/org.eclipse.osgi/container/src/org/eclipse/osgi/internal/hooks/DevClassLoadingHook.java
+++ b/bundles/org.eclipse.osgi/container/src/org/eclipse/osgi/internal/hooks/DevClassLoadingHook.java
@@ -79,7 +79,7 @@
 				if (!fromFragment && devCP.indexOf("..") >= 0) { //$NON-NLS-1$
 					// if in dev mode, try using cp as a relative path from the base bundle file
 					File base = sourceGeneration.getBundleFile().getBaseFile();
-					if (base.isDirectory()) {
+					if (base != null && base.isDirectory()) {
 						// this is only supported for directory bundles
 						ClasspathEntry entry = hostmanager.getExternalClassPath(new File(base, devCP).getAbsolutePath(), sourceGeneration);
 						if (entry != null) {