SLIDER-644 Add missing license header.
diff --git a/slider-core/src/main/java/org/apache/slider/common/params/ActionDiagnosticArgs.java b/slider-core/src/main/java/org/apache/slider/common/params/ActionDiagnosticArgs.java
index 9feeea4..4b03336 100644
--- a/slider-core/src/main/java/org/apache/slider/common/params/ActionDiagnosticArgs.java
+++ b/slider-core/src/main/java/org/apache/slider/common/params/ActionDiagnosticArgs.java
@@ -1,3 +1,20 @@
+/*
+ * 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.slider.common.params;
import com.beust.jcommander.Parameter;
