Enable Java 10 testing on Travis (#1224)

.travis.yml

@@ -8,25 +8,25 @@ cache:
 
 matrix:
   include:
-    - jdk: oraclejdk8 
+    - jdk: oraclejdk10
       dist: trusty
       group: edge
       sudo: required
-      addons:
-        apt:
-          packages:
-            - oracle-java8-installer
-      before_script: 
+      before_script:
         - "cd h2"
         - "echo $JAVA_OPTS"
         - "export JAVA_OPTS=-Xmx512m"
-    - jdk: openjdk7 
+    - jdk: oraclejdk8
       dist: trusty
       group: edge
       sudo: required
-      addons:
-        apt:
-          packages:
-            - openjdk-7-jdk
-      before_script: 
+      before_script:
+        - "cd h2"
+        - "echo $JAVA_OPTS"
+        - "export JAVA_OPTS=-Xmx512m"
+    - jdk: openjdk7
+      dist: trusty
+      group: edge
+      sudo: required
+      before_script:
         - "cd h2"