Added JDK 1.7 compiler plugin

Author: rijnb

pom.xml

@@ -68,6 +68,7 @@
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
+        <jdk.version>1.7</jdk.version>
 
         <gson.version>2.3</gson.version>
         <jsr305.version>3.0.0</jsr305.version>
@@ -78,6 +79,7 @@
         <maven-source-plugin.version>2.3</maven-source-plugin.version>
         <maven-javadoc-plugin.version>2.10</maven-javadoc-plugin.version>
         <maven-gpg-plugin.version>1.5</maven-gpg-plugin.version>
+        <maven-compiler-plugin.version>3.1</maven-compiler-plugin.version>
     </properties>
 
     <distributionManagement>
@@ -143,6 +145,16 @@
                     </execution>
                 </executions>
             </plugin>
+
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>${maven-compiler-plugin.version}</version>
+                <configuration>
+                    <source>${jdk.version}</source>
+                    <target>${jdk.version}</target>
+                </configuration>
+            </plugin>
         </plugins>
     </build>