Travis Java9 build.

.travis.yml

@@ -1,13 +1,36 @@
-language: java
 sudo: false
+language: java
+
+before_script:
+  - if [[ "x$JDK" == *'x9'* ]]; then remove_dir_from_path $JAVA_HOME/bin; export JAVA_HOME=/usr/lib/jvm/java-9-oracle; export PATH=$JAVA_HOME/bin:$PATH; java -Xmx32m -version; fi
+
+script:
+  - export JDK8_HOME=$(jdk_switcher home oraclejdk8)
+  - export JDK9_HOME=/usr/lib/jvm/java-9-oracle
+  - test -d "${JDK9_HOME}" || export JDK9_HOME=$(jdk_switcher home oraclejdk8)
+
+before_cache:
+  # No sense in caching current build artifacts
+  - rm -rf $HOME/.m2/repository/com/zaxxer
+
 cache:
   directories:
     - $HOME/.m2/repository
-jdk:
-  - oraclejdk8
+
+matrix:
+  fast_finish: true
+  include:
+    - jdk: oraclejdk8
+    - jdk: oraclejdk8 # this will be overridden by before_script above
+      addons:
+        apt:
+          packages:
+            - oracle-java9-installer
+      env:
+        - JDK=9
 
 install: /bin/true
 
 script:
   - mvn install -Dskip.unit.tests=true -Dmaven.javadoc.skip=true -V -B
-  - mvn test coveralls:report -V -P coverage 
+  - mvn test coveralls:report -V -P coverage

pom.xml

@@ -39,6 +39,7 @@
 
    <properties>
       <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+      <sureFireOptions9></sureFireOptions9>
 
       <felix.bundle.plugin.version>3.3.0</felix.bundle.plugin.version>
       <felix.version>5.6.2</felix.version>
@@ -368,11 +369,7 @@
                <version>2.19.1</version>
                <configuration>
                   <!-- Sets the VM argument line used when unit tests are run. -->
-                  <argLine>${surefireArgLine}
-                     --add-opens java.base/java.net=ALL-UNNAMED
-                     --add-opens java.base/java.security=ALL-UNNAMED
-                     --add-exports java.base/sun.net.www.protocol.http=ALL-UNNAMED
-                     --add-exports java.base/sun.net.www.protocol.https=ALL-UNNAMED</argLine>
+                  <argLine>${surefireArgLine} ${sureFireOptions9}</argLine>
                   <!-- Skips unit tests if the value of skip.unit.tests property is true -->
                   <skipTests>${skip.unit.tests}</skipTests>
                   <reuseForks>true</reuseForks>
@@ -423,6 +420,21 @@
    </build>
 
    <profiles>
+      <profile>
+         <id>Java9</id>
+         <activation>
+            <jdk>[9,)</jdk>
+         </activation>
+         <properties>
+            <sureFireOptions9>
+               --add-opens java.base/java.net=ALL-UNNAMED
+               --add-opens java.base/java.security=ALL-UNNAMED
+               --add-exports java.base/sun.net.www.protocol.http=ALL-UNNAMED
+               --add-exports java.base/sun.net.www.protocol.https=ALL-UNNAMED
+            </sureFireOptions9>
+         </properties>
+      </profile>
+
       <profile>
          <id>coverage</id>
          <build>