This closes #1697

artemis-jms-client/src/main/java/org/apache/activemq/artemis/jms/client/ActiveMQMessage.java

@@ -742,6 +742,8 @@ public class ActiveMQMessage implements javax.jms.Message {
    public <T> T getBody(Class<T> c) throws JMSException {
       if (isBodyAssignableTo(c)) {
          return getBodyInternal(c);
+      } else if (hasNoBody()) {
+         return null;
       }
       // XXX HORNETQ-1209 Do we need translations here?
       throw new MessageFormatException("Body not assignable to " + c);

tests/integration-tests/src/test/java/org/apache/activemq/artemis/tests/integration/jms/jms2client/BodyTest.java

@@ -20,12 +20,12 @@ import javax.jms.BytesMessage;
 import javax.jms.Connection;
 import javax.jms.Message;
 import javax.jms.MessageConsumer;
-import javax.jms.MessageFormatException;
 import javax.jms.MessageProducer;
 import javax.jms.Session;
 
 import org.apache.activemq.artemis.api.jms.ActiveMQJMSClient;
 import org.apache.activemq.artemis.tests.util.JMSTestBase;
+import org.junit.Assert;
 import org.junit.Before;
 import org.junit.Test;
 
@@ -48,7 +48,6 @@ public class BodyTest extends JMSTestBase {
       try (
          Connection conn = cf.createConnection();
       ) {
-
          Session sess = conn.createSession();
          MessageProducer producer = sess.createProducer(queue);
 
@@ -56,17 +55,27 @@ public class BodyTest extends JMSTestBase {
          conn.start();
 
          BytesMessage bytesMessage = sess.createBytesMessage();
+         BytesMessage bytesMessage2 = sess.createBytesMessage();
+         bytesMessage2.writeInt(42);
+         bytesMessage2.reset();
+
          producer.send(bytesMessage);
-
          Message msg = cons.receiveNoWait();
+
+         producer.send(bytesMessage2);
+         Message msg2 = cons.receiveNoWait();
+
          assertNotNull(msg);
+         assertNotNull(msg2);
 
-         try {
-            msg.getBody(String.class);
-            fail("Exception expected");
-         } catch (MessageFormatException e) {
-         }
+         // message body is empty. getBody parameter may be set to any type
+         Assert.assertNull(msg.getBody(java.lang.Object.class));
+         Assert.assertNull(msg.getBody(byte[].class));
+         Assert.assertNull(msg.getBody(String.class));
+
+         // message body is not empty. getBody parameter must be set to byte[].class (or java.lang.Object.class)
+         Assert.assertNotNull(msg2.getBody(byte[].class));
+         Assert.assertNotNull(msg2.getBody(java.lang.Object.class));
       }
-
    }
 }

tests/jms-tests/src/test/java/org/apache/activemq/artemis/jms/tests/message/BodyIsAssignableFromTest.java

@@ -94,7 +94,7 @@ public class BodyIsAssignableFromTest extends MessageBodyTestCase {
          } else {
             try {
                Object foo = msg.getBody(c);
-               Assert.fail("expected a " + MessageFormatException.class);
+               Assert.assertNull("body should be null", foo);
             } catch (MessageFormatException e) {
                // expected
             }