add style check for java and scala code

jvm-packages/checkstyle-suppressions.xml

@@ -0,0 +1,33 @@
+<!--
+  ~ 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.
+  -->
+
+<!DOCTYPE suppressions PUBLIC
+"-//Puppy Crawl//DTD Suppressions 1.1//EN"
+"http://www.puppycrawl.com/dtds/suppressions_1_1.dtd">
+
+<!--
+
+    This file contains suppression rules for Checkstyle checks.
+    Ideally only files that cannot be modified (e.g. third-party code)
+    should be added here. All other violations should be fixed.
+
+-->
+
+<suppressions>
+<suppress checks=".*"
+	files="xgboost4j/src/main/java/org/dmlc/xgboost4j/XgboostJNI.java"/>
+</suppressions>