Adds Java 6 and 7 to Travis build matrix.

Author: sebright2

.travis.yml

@@ -2,16 +2,35 @@ sudo: required
 dist: trusty
 language: java
 
-jdk:
-  - oraclejdk8
+matrix:
+  include:
+  - jdk: openjdk6
+    env: BUILD=MVN
+
+  - jdk: oraclejdk7
+    env: BUILD=MVN
+
+  - jdk: oraclejdk8
+    env: BUILD=BAZEL
 
 before_install:
-  - echo "deb [arch=amd64] http://storage.googleapis.com/bazel-apt stable jdk1.8" | sudo tee /etc/apt/sources.list.d/bazel.list
-  - curl https://storage.googleapis.com/bazel-apt/doc/apt-key.pub.gpg | sudo apt-key add -
-  - sudo apt-get update
+  - case "$BUILD" in
+      "BAZEL")
+        echo "deb [arch=amd64] http://storage.googleapis.com/bazel-apt stable jdk1.8" | sudo tee /etc/apt/sources.list.d/bazel.list ;
+        curl https://storage.googleapis.com/bazel-apt/doc/apt-key.pub.gpg | sudo apt-key add - ;
+        sudo apt-get update ;;
+    esac
 
 install:
-  - sudo apt-get install bazel
+  - case "$BUILD" in
+      "BAZEL")
+        sudo apt-get install bazel ;;
+    esac
 
 script:
-  - bazel test ...
+  - case "$BUILD" in
+      "BAZEL")
+        bazel test ... ;;
+      "MVN")
+        mvn package ;;
+    esac