Add explicit SCM dependencies in pom.xml (#1505)

java/pom.xml

@@ -143,8 +143,9 @@
         </executions>
       </plugin>
       <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-release-plugin</artifactId>
-        <version>2.2.1</version>
+        <version>2.5.2</version>
         <configuration>
           <tagNameFormat>v@{project.version}</tagNameFormat>
         </configuration>
@@ -191,6 +192,24 @@
     </profile>
   </profiles>
 
+  <!-- Until 08. Dec 2016, this pom worked with maven-release-plugin at 2.2.1
+       and default SCM dependencies. On 11. Jan, 2017 that was no longer the
+       case, presumably because the default SCM version changed (cannot find
+       references), and the 2.5.2, 1.9.4 versions ended up working. -->
+  <dependencyManagement>
+    <dependencies>
+      <dependency>
+        <groupId>org.apache.maven.scm</groupId>
+        <artifactId>maven-scm-api</artifactId>
+        <version>1.9.4</version>
+      </dependency>
+      <dependency>
+        <groupId>org.apache.maven.scm</groupId>
+        <artifactId>maven-scm-provider-gitexe</artifactId>
+        <version>1.9.4</version>
+      </dependency>
+    </dependencies>
+  </dependencyManagement>
   <dependencies>
     <dependency>
       <groupId>junit</groupId>