Build Java 9 on Travis; update plugins

.travis.yml

@@ -14,6 +14,8 @@ matrix:
    - jdk: oraclejdk8
      env: ANDROID_HOME=$HOME/android-sdk-linux
      before_install: if [ ! -d $HOME/android-sdk-linux/platforms ]; then curl -s https://storage.googleapis.com/zxing-build/android-sdk-linux.tar.bz2 | bunzip2 | tar xf - -C $HOME; else ls -l $HOME/android-sdk-linux; fi
+   # Covers Java 9
+   - jdk: oraclejdk9
 cache:
   directories:
     - $HOME/.m2

pom.xml

@@ -158,7 +158,7 @@
         <plugin>
           <groupId>org.apache.maven.plugins</groupId>
           <artifactId>maven-compiler-plugin</artifactId>
-          <version>3.6.2</version>
+          <version>3.7.0</version>
           <configuration>
             <source>${java.version}</source>
             <target>${java.version}</target>
@@ -237,7 +237,7 @@
         <plugin>
           <groupId>org.apache.maven.plugins</groupId>
           <artifactId>maven-assembly-plugin</artifactId>
-          <version>3.0.0</version>
+          <version>3.1.0</version>
         </plugin>
         <plugin>
           <groupId>org.apache.maven.plugins</groupId>
@@ -297,7 +297,7 @@
         <plugin>
           <groupId>org.apache.maven.plugins</groupId>
           <artifactId>maven-dependency-plugin</artifactId>
-          <version>3.0.1</version>
+          <version>3.0.2</version>
         </plugin>
         <plugin>
           <groupId>org.apache.maven.plugins</groupId>
@@ -325,7 +325,7 @@
         <plugin>
           <groupId>org.apache.maven.plugins</groupId>
           <artifactId>maven-surefire-plugin</artifactId>
-          <version>2.20</version>
+          <version>2.20.1</version>
           <configuration>
             <forkCount>0.5C</forkCount>
             <systemPropertyVariables>