Increasing Java version to 1.7 to be compatible with other poms

tools/java/common/pom.xml

@@ -1,5 +1,7 @@
 <?xml version="1.0"?>
-<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns="http://maven.apache.org/POM/4.0.0"
+<project
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"
+    xmlns="http://maven.apache.org/POM/4.0.0"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
   <modelVersion>4.0.0</modelVersion>
 
@@ -29,9 +31,9 @@
         <artifactId>maven-compiler-plugin</artifactId>
         <version>2.0.2</version>
         <configuration>
-          <source>1.6</source>
-	  <target>1.6</target>
-	  <encoding>UTF-8</encoding>
+          <source>1.7</source>
+          <target>1.7</target>
+          <encoding>UTF-8</encoding>
         </configuration>
       </plugin>
       <!-- Add ../../../java/libphonenumber/src/ to make Phonemetadata.java available to the source