diff --git a/solrdf/src/main/java/org/gazzax/labs/solrdf/handler/update/Sparql11UpdateRdfDataLoader.java b/solrdf/src/main/java/org/gazzax/labs/solrdf/handler/update/Sparql11UpdateRdfDataLoader.java
index 7e1ec52..ff0cc31 100644
--- a/solrdf/src/main/java/org/gazzax/labs/solrdf/handler/update/Sparql11UpdateRdfDataLoader.java
+++ b/solrdf/src/main/java/org/gazzax/labs/solrdf/handler/update/Sparql11UpdateRdfDataLoader.java
@@ -1,5 +1,9 @@
 package org.gazzax.labs.solrdf.handler.update;
 
+import static org.gazzax.labs.solrdf.Strings.isNullOrEmptyString;
+
+import org.apache.solr.common.SolrException;
+import org.apache.solr.common.SolrException.ErrorCode;
 import org.apache.solr.common.params.CommonParams;
 import org.apache.solr.common.util.ContentStream;
 import org.apache.solr.handler.loader.ContentStreamLoader;
@@ -30,10 +34,14 @@ public void load(
 			final ContentStream stream, 
 			final UpdateRequestProcessor processor) throws Exception {
 		
+		final String q = request.getParams().get(CommonParams.Q);
+		if (isNullOrEmptyString(q)) {
+			throw new SolrException(ErrorCode.BAD_REQUEST, "Invalid query : " + q);
+		}
+		
 		UpdateAction.execute(
 				UpdateFactory.create(
 						request.getParams().get(CommonParams.Q)),
 						new SolRDFDatasetGraph(request, response));
-		
 	}
 }	
\ No newline at end of file
diff --git a/solrdf/src/test/java/org/gazzax/labs/solrdf/handler/Sparql11GraphStoreProtocolHandlerTestCase.java b/solrdf/src/test/java/org/gazzax/labs/solrdf/handler/Sparql11GraphStoreProtocolHandlerTestCase.java
index 1460199..f4425cb 100644
--- a/solrdf/src/test/java/org/gazzax/labs/solrdf/handler/Sparql11GraphStoreProtocolHandlerTestCase.java
+++ b/solrdf/src/test/java/org/gazzax/labs/solrdf/handler/Sparql11GraphStoreProtocolHandlerTestCase.java
@@ -1,9 +1,9 @@
 package org.gazzax.labs.solrdf.handler;
 
-import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
-import static org.mockito.Mockito.*;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
 
 import java.util.HashMap;
 import java.util.HashSet;
@@ -12,7 +12,6 @@
 
 import javax.servlet.http.HttpServletRequest;
 
-import org.apache.solr.common.params.CommonParams;
 import org.apache.solr.common.params.ModifiableSolrParams;
 import org.apache.solr.core.SolrCore;
 import org.apache.solr.request.SolrQueryRequest;
diff --git a/solrdf/src/test/java/org/gazzax/labs/solrdf/handler/update/Sparql11UpdateRdfDataLoaderTestCase.java b/solrdf/src/test/java/org/gazzax/labs/solrdf/handler/update/Sparql11UpdateRdfDataLoaderTestCase.java
new file mode 100644
index 0000000..83ef43d
--- /dev/null
+++ b/solrdf/src/test/java/org/gazzax/labs/solrdf/handler/update/Sparql11UpdateRdfDataLoaderTestCase.java
@@ -0,0 +1,85 @@
+package org.gazzax.labs.solrdf.handler.update;
+
+import static org.gazzax.labs.solrdf.TestUtility.randomString;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+import org.apache.solr.common.SolrException;
+import org.apache.solr.common.SolrException.ErrorCode;
+import org.apache.solr.common.params.CommonParams;
+import org.apache.solr.common.params.ModifiableSolrParams;
+import org.apache.solr.common.util.ContentStream;
+import org.apache.solr.request.SolrQueryRequest;
+import org.apache.solr.response.SolrQueryResponse;
+import org.apache.solr.update.processor.UpdateRequestProcessor;
+import org.junit.Before;
+import org.junit.Test;
+
+import com.hp.hpl.jena.query.QueryParseException;
+
+/**
+ * Test case for {@link Sparql11UpdateRdfDataLoader}.
+ * 
+ * @author Andrea Gazzarini
+ * @since 1.0
+ */
+public class Sparql11UpdateRdfDataLoaderTestCase {
+	private Sparql11UpdateRdfDataLoader cut;
+	private SolrQueryRequest request;
+	private SolrQueryResponse response;
+	private ContentStream stream;
+	private UpdateRequestProcessor processor;
+	private ModifiableSolrParams parameters;
+	
+	@Before
+	public void setUp() {
+		cut = new Sparql11UpdateRdfDataLoader();
+		request = mock(SolrQueryRequest.class);
+		response = mock(SolrQueryResponse.class);
+		parameters = new ModifiableSolrParams();
+		stream = mock(ContentStream.class);
+		processor = mock(UpdateRequestProcessor.class);
+		
+		when(request.getParams()).thenReturn(parameters);
+	}
+	
+	/** 
+	 * In case of a null query a {@link QueryParseException} must be raised.
+	 */
+	@Test
+	public void nullOrEmptyQuery() {
+		final String [] invalidQueries = {"", "   "};
+		for (final String invalidQuery : invalidQueries) {
+			parameters.set(CommonParams.Q, invalidQuery);
+			try {
+				cut.load(request, response, stream, processor);
+				fail();
+			} catch (final Exception expected) {
+				assertTrue(expected instanceof SolrException);
+				assertEquals(ErrorCode.BAD_REQUEST.code, ((SolrException)expected).code());
+			}
+		}
+	}
+	
+	/** 
+	 * In case of an invalid query a {@link QueryParseException} must be raised.
+	 */
+	@Test
+	public void invalidQuery() {
+		final String [] invalidQueries = {"BLABALBALABLA", randomString()};
+		
+		for (final String invalidQuery : invalidQueries) {
+			parameters.set(CommonParams.Q, invalidQuery);
+			try {
+				cut.load(request, response, stream, processor);
+				fail();
+			} catch (final Exception expected) {
+				assertTrue(expected instanceof QueryParseException);
+			}					
+		}
+	}
+}
\ No newline at end of file