Merge pull request #28 from amichair/illegalstate

Add explicit IllegalStateException in exportService
diff --git a/rsa/src/main/java/org/apache/aries/rsa/core/RemoteServiceAdminCore.java b/rsa/src/main/java/org/apache/aries/rsa/core/RemoteServiceAdminCore.java
index 40c3f93..d48283c 100644
--- a/rsa/src/main/java/org/apache/aries/rsa/core/RemoteServiceAdminCore.java
+++ b/rsa/src/main/java/org/apache/aries/rsa/core/RemoteServiceAdminCore.java
@@ -225,6 +225,9 @@
             }
             final BundleContext serviceContext = serviceBundle.getBundleContext();
             final Object serviceO = serviceContext.getService(serviceReference);
+            if (serviceO == null) {
+                throw new IllegalStateException("service object is null (service was unregistered?)");
+            }
             final Class<?>[] interfaces = getInterfaces(serviceO, interfaceNames);
             final Map<String, Object> eprops = createEndpointProps(serviceProperties, interfaces);