Add Google Java Formatter as an action, and apply it.

.github/workflows/java-formatter.yml

@@ -0,0 +1,20 @@
+name: Google Java Formatter
+
+on:
+  push:
+    branches:
+      - master
+
+jobs:
+
+  formatting:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2 # v2 minimum required
+      # Recommended: latest versions of Google Java Format require JDK 11+
+      - uses: actions/setup-java@v1
+        with:
+          java-version: "11"
+      - uses: axel-op/googlejavaformat-action@v3
+        with:
+          args: "--replace"

.github/workflows/scalaformatter.yml

@@ -14,3 +14,5 @@ jobs:
           fetch-depth: 1
       - name: Running scalafmt
         uses: openlawteam/scalafmt-ci@v2
+        with:
+          args: ''

.travis.yml

@@ -1,4 +1,4 @@
-dist: xenial
+dist: bionic
 language: java
 
 branches:

pom.xml

@@ -25,7 +25,6 @@
     <hadoop.version>2.7.4</hadoop.version>
     <spark.version>3.0.0</spark.version>
     <github.global.server>github</github.global.server>
-    <checkstyle.plugin.version>2.17</checkstyle.plugin.version>
     <license.plugin.version>3.0</license.plugin.version>
     <release.plugin.version>2.5.2</release.plugin.version>
     <scm-provider-gitexe.plugin.version>1.9.5</scm-provider-gitexe.plugin.version>
@@ -171,54 +170,6 @@
           </args>
         </configuration>
       </plugin>
-      <!-- For checkstyle. -->
-      <plugin>
-        <groupId>org.apache.maven.plugins</groupId>
-        <artifactId>maven-checkstyle-plugin</artifactId>
-        <version>${checkstyle.plugin.version}</version>
-        <configuration>
-          <includeTestSourceDirectory>true</includeTestSourceDirectory>
-          <consoleOutput>true</consoleOutput>
-          <logViolationsToConsole>true</logViolationsToConsole>
-          <failsOnError>true</failsOnError>
-          <failOnViolation>true</failOnViolation>
-          <violationSeverity>warning</violationSeverity>
-          <suppressionsLocation>config/checkstyle/suppressions.xml</suppressionsLocation>
-        </configuration>
-        <executions>
-          <execution>
-            <id>checkstyle</id>
-            <phase>verify</phase>
-            <goals>
-              <goal>check</goal>
-            </goals>
-          </execution>
-        </executions>
-      </plugin>
-      <!-- For scalastyle. -->
-      <plugin>
-        <groupId>org.scalastyle</groupId>
-        <artifactId>scalastyle-maven-plugin</artifactId>
-        <version>1.0.0</version>
-        <configuration>
-          <verbose>false</verbose>
-          <failOnViolation>true</failOnViolation>
-          <includeTestSourceDirectory>true</includeTestSourceDirectory>
-          <failOnWarning>false</failOnWarning>
-          <sourceDirectory>${project.basedir}/src/main/scala</sourceDirectory>
-          <testSourceDirectory>${project.basedir}/src/test/scala</testSourceDirectory>
-          <configLocation>${project.basedir}/config/checkstyle/scalastyle_config.xml</configLocation>
-          <outputFile>${project.basedir}/target/scalastyle-output.xml</outputFile>
-          <outputEncoding>UTF-8</outputEncoding>
-        </configuration>
-        <executions>
-          <execution>
-            <goals>
-              <goal>check</goal>
-            </goals>
-          </execution>
-        </executions>
-      </plugin>
       <!-- For license header enforcement. -->
       <plugin>
         <groupId>com.mycila</groupId>