[Build] Build on OpenJdk8

Author: mpkorstanje

.m2/travis-ci-toolchains.xml

@@ -3,11 +3,11 @@
     <toolchain>
         <type>jdk</type>
         <provides>
-            <version>11</version>
+            <version>8</version>
             <vendor>openjdk</vendor>
         </provides>
         <configuration>
-            <jdkHome>/usr/local/lib/jvm/openjdk11</jdkHome>
+            <jdkHome>/usr/local/lib/jvm/openjdk8</jdkHome>
         </configuration>
     </toolchain>
 </toolchains>

.travis.yml

@@ -10,15 +10,15 @@ jobs:
   - stage: test
     scala: 2.11
     script: mvn test -pl scala/scala_2.11 -B --toolchains .m2/travis-ci-toolchains.xml
-    jdk: openjdk11
+    jdk: openjdk8
   - stage: test
     scala: 2.12
     script: mvn test -pl scala/scala_2.12,examples -B --toolchains .m2/travis-ci-toolchains.xml
-    jdk: openjdk11
+    jdk: openjdk8
   - stage: test
     scala: 2.13
     script: mvn test -pl scala/scala_2.13,examples -B --toolchains .m2/travis-ci-toolchains.xml
-    jdk: openjdk11
+    jdk: openjdk8
 branches:
   only:
   - master