This closes #799

artemis-core-client/src/main/java/org/apache/activemq/artemis/api/core/JsonUtil.java

@@ -231,6 +231,9 @@ public final class JsonUtil {
       else if (param instanceof SimpleString) {
          jsonObjectBuilder.add(key, param.toString());
       }
+      else if (param == null) {
+         jsonObjectBuilder.addNull(key);
+      }
       else {
          throw ActiveMQClientMessageBundle.BUNDLE.invalidManagementParam(param.getClass().getName());
       }
@@ -262,6 +265,9 @@ public final class JsonUtil {
       else if (param instanceof Byte) {
          jsonArrayBuilder.add(((Byte) param).shortValue());
       }
+      else if (param == null) {
+         jsonArrayBuilder.addNull();
+      }
       else {
          throw ActiveMQClientMessageBundle.BUNDLE.invalidManagementParam(param.getClass().getName());
       }

artemis-core-client/src/test/java/org/apache/activemq/artemis/api/core/JsonUtilTest.java

@@ -0,0 +1,56 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.activemq.artemis.api.core;
+
+import javax.json.JsonArray;
+import javax.json.JsonArrayBuilder;
+import javax.json.JsonObject;
+import javax.json.JsonObjectBuilder;
+
+import org.apache.activemq.artemis.utils.JsonLoader;
+import org.junit.Assert;
+import org.junit.Test;
+
+public class JsonUtilTest {
+
+   @Test
+   public void testAddToObject() {
+      JsonObjectBuilder jsonObjectBuilder = JsonLoader.createObjectBuilder();
+
+      JsonUtil.addToObject("not-null", "not-null", jsonObjectBuilder);
+      JsonUtil.addToObject("null", null, jsonObjectBuilder);
+
+      JsonObject jsonObject = jsonObjectBuilder.build();
+
+      Assert.assertTrue(jsonObject.containsKey("not-null"));
+      Assert.assertTrue(jsonObject.containsKey("null"));
+      Assert.assertEquals(2, jsonObject.size());
+   }
+
+   @Test
+   public void testAddToArray() {
+      JsonArrayBuilder jsonArrayBuilder = JsonLoader.createArrayBuilder();
+
+      JsonUtil.addToArray("hello", jsonArrayBuilder);
+      JsonUtil.addToArray(null, jsonArrayBuilder);
+
+      JsonArray jsonArray = jsonArrayBuilder.build();
+
+      Assert.assertEquals(2, jsonArray.size());
+   }
+}