[BUILD] add licensing check on compile

Original commit: elastic/x-pack-elasticsearch@cfd2e1a3e5

dev-tools/elasticsearch_license_header.txt

@@ -0,0 +1,15 @@
+ELASTICSEARCH CONFIDENTIAL
+__________________
+
+ [2014] Elasticsearch Incorporated
+ All Rights Reserved.
+
+NOTICE:  All information contained herein is, and remains
+the property of Elasticsearch Incorporated and its suppliers,
+if any.  The intellectual and technical concepts contained
+herein are proprietary to Elasticsearch Incorporated
+and its suppliers and may be covered by U.S. and Foreign Patents,
+patents in process, and are protected by trade secret or copyright law.
+Dissemination of this information or reproduction of this material
+is strictly forbidden unless prior written permission is obtained
+from Elasticsearch Incorporated.

dev-tools/license_header_definition.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<additionalHeaders>
+    <javadoc_style>
+        <firstLine>/*</firstLine>
+        <beforeEachLine> * </beforeEachLine>
+        <endLine> */</endLine>
+        <!--skipLine></skipLine-->
+        <firstLineDetectionPattern>(\s|\t)*/\*.*$</firstLineDetectionPattern>
+        <lastLineDetectionPattern>.*\*/(\s|\t)*$</lastLineDetectionPattern>
+        <allowBlankLines>false</allowBlankLines>
+        <isMultiline>true</isMultiline>
+    </javadoc_style>
+</additionalHeaders>

pom.xml

@@ -175,9 +175,6 @@
                     </compilerArgs>
                 </configuration>
             </plugin>
-            <!-- ============================================================= -->
-            <!-- Optional. This plugin is using surefire plugin to run tests.  -->
-            <!-- ============================================================= -->
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-surefire-plugin</artifactId>
@@ -190,9 +187,6 @@
                     </includes>
                 </configuration>
             </plugin>
-            <!-- ============================================================= -->
-            <!-- This plugin assembles plugin .zip package.                     -->
-            <!-- ============================================================= -->
             <plugin>
                 <artifactId>maven-assembly-plugin</artifactId>
                 <version>2.4</version>
@@ -301,18 +295,41 @@
                     </execution>
                 </executions>
             </plugin>
+            <plugin>
+                <groupId>com.mycila</groupId>
+                <artifactId>license-maven-plugin</artifactId>
+                <version>2.5</version>
+                <configuration>
+                    <header>dev-tools/elasticsearch_license_header.txt</header>
+                    <headerDefinitions>
+                        <headerDefinition>dev-tools/license_header_definition.xml</headerDefinition>
+                    </headerDefinitions>
+                    <includes>
+                        <include>src/main/java/org/elasticsearch/**/*.java</include>
+                        <include>src/test/java/org/elasticsearch/**/*.java</include>
+                    </includes>
+                </configuration>
+                <executions>
+                    <execution>
+                        <phase>compile</phase>
+                        <goals>
+                            <goal>check</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
         </plugins>
     </build>
     <profiles>
-      <profile>
+        <profile>
-        <id>artifactory-private</id>
+            <id>artifactory-private</id>
-        <distributionManagement>
+            <distributionManagement>
-          <snapshotRepository>
+                <snapshotRepository>
-            <id>snapshots</id>
+                    <id>snapshots</id>
-            <name>artifactory.elasticsearch.org-snapshots</name>
+                    <name>artifactory.elasticsearch.org-snapshots</name>
-            <url>https://artifactory.elasticsearch.org/artifactory/libs-snapshot-local</url>
+                    <url>https://artifactory.elasticsearch.org/artifactory/libs-snapshot-local</url>
-          </snapshotRepository>
+                </snapshotRepository>
-        </distributionManagement>
+            </distributionManagement>
-      </profile>
+        </profile>
     </profiles>
 </project>