Fix Travis CI -> SDK 24

.travis.yml

@@ -1,20 +1,24 @@
 language: android
-
-sudo: false
-
 jdk:
-  - oraclejdk7
-
+  - oraclejdk8
 android:
   components:
-    - platform-tools
     - tools
-    - android-23
-    - build-tools-23.0.3
-    - extra-google-m2repository
+    - tools # TODO https://github.com/travis-ci/travis-ci/issues/6193
+    - platform-tools
+    - build-tools-24.0.0
+    - android-24
     - extra-android-m2repository
-
-script: ./gradlew build check --stacktrace
+before_cache:
+  - rm -f $HOME/.gradle/caches/modules-2/modules-2.lock
+cache:
+  directories:
+    - $HOME/.gradle/caches/
+    - $HOME/.gradle/wrapper/
+script: "./gradlew $TASK"
+env:
+    - TASK="lintDebug"
+    - TASK="build check --stacktrace"
 
 notifications:
   webhooks: