Set source and target to Java 6 in Android Studio.

briar-android/briar-android.iml

@@ -23,7 +23,7 @@
       </configuration>
     </facet>
   </component>
-  <component name="NewModuleRootManager" LANGUAGE_LEVEL="JDK_1_7" inherit-compiler-output="false">
+  <component name="NewModuleRootManager" LANGUAGE_LEVEL="JDK_1_6" inherit-compiler-output="false">
     <output url="file://$MODULE_DIR$/build/intermediates/classes/debug" />
     <output-test url="file://$MODULE_DIR$/build/intermediates/classes/test/debug" />
     <exclude-output />

briar-android/build.gradle

@@ -35,4 +35,8 @@ android {
         debug.setRoot('build-types/debug')
         release.setRoot('build-types/release')
     }
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_6
+        targetCompatibility JavaVersion.VERSION_1_6
+    }
 }

briar.iml

@@ -8,7 +8,7 @@
       </configuration>
     </facet>
   </component>
-  <component name="NewModuleRootManager" LANGUAGE_LEVEL="JDK_1_7" inherit-compiler-output="true">
+  <component name="NewModuleRootManager" LANGUAGE_LEVEL="JDK_1_6" inherit-compiler-output="true">
     <exclude-output />
     <content url="file://$MODULE_DIR$">
       <excludeFolder url="file://$MODULE_DIR$/.gradle" />