diff --git a/appveyor.yml b/appveyor.yml
index 4f14e239876d..fdf40cfba8b0 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -98,7 +98,7 @@ build_script:
         cmake .. -G"%generator%" -DCMAKE_CONFIGURATION_TYPES="Release" -DR_LIB=ON &&
         cmake --build . --target install --config Release
       )
-    - if /i "%target%" == "jvm" cd jvm-packages && mvn test -pl :xgboost4j
+    - if /i "%target%" == "jvm" cd jvm-packages && mvn test -pl :xgboost4j_2.12
 
 test_script:
     - cd %APPVEYOR_BUILD_FOLDER%
diff --git a/jvm-packages/README.md b/jvm-packages/README.md
index 0f8cd16ea2c7..e03b166b3260 100644
--- a/jvm-packages/README.md
+++ b/jvm-packages/README.md
@@ -27,14 +27,14 @@ XGBoost4J, XGBoost4J-Spark, etc. in maven repository is compiled with g++-4.8.5
 ```
 <dependency>
     <groupId>ml.dmlc</groupId>
-    <artifactId>xgboost4j</artifactId>
+    <artifactId>xgboost4j_2.12</artifactId>
     <version>latest_version_num</version>
 </dependency>
 ``` 
  
 <b>sbt</b> 
 ```sbt
- "ml.dmlc" % "xgboost4j" % "latest_version_num"
+ "ml.dmlc" %% "xgboost4j" % "latest_version_num"
 ``` 
 
 For the latest release version number, please check [here](https://github.com/dmlc/xgboost/releases).
@@ -68,17 +68,17 @@ the add dependency as following:
 ```
 <dependency>
     <groupId>ml.dmlc</groupId>
-    <artifactId>xgboost4j</artifactId>
+    <artifactId>xgboost4j_2.12</artifactId>
     <version>latest_version_num</version>
 </dependency>
 ``` 
  
 <b>sbt</b> 
 ```sbt
- "ml.dmlc" % "xgboost4j" % "latest_version_num"
+ "ml.dmlc" %% "xgboost4j" % "latest_version_num"
 ``` 
 
-For the latest release version number, please check [here](https://github.com/CodingCat/xgboost/tree/maven-repo/ml/dmlc/xgboost4j).
+For the latest release version number, please check [here](https://github.com/CodingCat/xgboost/tree/maven-repo/ml/dmlc/xgboost4j_2.12).
 
 if you want to use `xgboost4j-spark`, you just need to replace xgboost4j with `xgboost4j-spark`
 
diff --git a/jvm-packages/pom.xml b/jvm-packages/pom.xml
index 1f3b0ca0f001..e74ca8bb0daf 100644
--- a/jvm-packages/pom.xml
+++ b/jvm-packages/pom.xml
@@ -5,7 +5,7 @@
     <modelVersion>4.0.0</modelVersion>
 
     <groupId>ml.dmlc</groupId>
-    <artifactId>xgboost-jvm</artifactId>
+    <artifactId>xgboost-jvm_2.12</artifactId>
     <version>0.90</version>
     <packaging>pom</packaging>
     <name>XGBoost JVM Package</name>
@@ -31,12 +31,12 @@
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
-        <maven.compiler.source>1.7</maven.compiler.source>
-        <maven.compiler.target>1.7</maven.compiler.target>
-        <flink.version>1.5.0</flink.version>
+        <maven.compiler.source>1.8</maven.compiler.source>
+        <maven.compiler.target>1.8</maven.compiler.target>
+        <flink.version>1.7.2</flink.version>
         <spark.version>2.4.3</spark.version>
-        <scala.version>2.11.12</scala.version>
-        <scala.binary.version>2.11</scala.binary.version>
+        <scala.version>2.12.8</scala.version>
+        <scala.binary.version>2.12</scala.binary.version>
     </properties>
     <repositories>
         <repository>
@@ -372,7 +372,13 @@
         <dependency>
             <groupId>org.scalatest</groupId>
             <artifactId>scalatest_${scala.binary.version}</artifactId>
-            <version>3.0.0</version>
+            <version>3.0.8</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.scalactic</groupId>
+            <artifactId>scalactic_${scala.binary.version}</artifactId>
+            <version>3.0.8</version>
             <scope>test</scope>
         </dependency>
     </dependencies>
diff --git a/jvm-packages/xgboost4j-example/pom.xml b/jvm-packages/xgboost4j-example/pom.xml
index 0c628f9dde40..ac0d495d2523 100644
--- a/jvm-packages/xgboost4j-example/pom.xml
+++ b/jvm-packages/xgboost4j-example/pom.xml
@@ -5,10 +5,10 @@
     <modelVersion>4.0.0</modelVersion>
     <parent>
         <groupId>ml.dmlc</groupId>
-        <artifactId>xgboost-jvm</artifactId>
+        <artifactId>xgboost-jvm_2.12</artifactId>
         <version>0.90</version>
     </parent>
-    <artifactId>xgboost4j-example</artifactId>
+    <artifactId>xgboost4j-example_2.12</artifactId>
     <version>0.90</version>
     <packaging>jar</packaging>
     <build>
@@ -25,7 +25,7 @@
     <dependencies>
         <dependency>
             <groupId>ml.dmlc</groupId>
-            <artifactId>xgboost4j-spark</artifactId>
+            <artifactId>xgboost4j-spark_${scala.binary.version}</artifactId>
             <version>0.90</version>
         </dependency>
         <dependency>
@@ -36,7 +36,7 @@
         </dependency>
         <dependency>
             <groupId>ml.dmlc</groupId>
-            <artifactId>xgboost4j-flink</artifactId>
+            <artifactId>xgboost4j-flink_${scala.binary.version}</artifactId>
             <version>0.90</version>
         </dependency>
         <dependency>
diff --git a/jvm-packages/xgboost4j-flink/pom.xml b/jvm-packages/xgboost4j-flink/pom.xml
index 3e249896e7d6..0be85d1ce7dd 100644
--- a/jvm-packages/xgboost4j-flink/pom.xml
+++ b/jvm-packages/xgboost4j-flink/pom.xml
@@ -5,10 +5,10 @@
     <modelVersion>4.0.0</modelVersion>
     <parent>
         <groupId>ml.dmlc</groupId>
-        <artifactId>xgboost-jvm</artifactId>
+        <artifactId>xgboost-jvm_2.12</artifactId>
         <version>0.90</version>
     </parent>
-    <artifactId>xgboost4j-flink</artifactId>
+    <artifactId>xgboost4j-flink_2.12</artifactId>
     <version>0.90</version>
     <build>
         <plugins>
@@ -25,7 +25,7 @@
     <dependencies>
         <dependency>
             <groupId>ml.dmlc</groupId>
-            <artifactId>xgboost4j</artifactId>
+            <artifactId>xgboost4j_${scala.binary.version}</artifactId>
             <version>0.90</version>
         </dependency>
         <dependency>
diff --git a/jvm-packages/xgboost4j-spark/pom.xml b/jvm-packages/xgboost4j-spark/pom.xml
index 2407a047fba8..09af42cf9950 100644
--- a/jvm-packages/xgboost4j-spark/pom.xml
+++ b/jvm-packages/xgboost4j-spark/pom.xml
@@ -5,10 +5,10 @@
     <modelVersion>4.0.0</modelVersion>
     <parent>
         <groupId>ml.dmlc</groupId>
-        <artifactId>xgboost-jvm</artifactId>
+        <artifactId>xgboost-jvm_2.12</artifactId>
         <version>0.90</version>
     </parent>
-    <artifactId>xgboost4j-spark</artifactId>
+    <artifactId>xgboost4j-spark_2.12</artifactId>
     <build>
         <plugins>
             <plugin>
@@ -23,7 +23,7 @@
     <dependencies>
         <dependency>
             <groupId>ml.dmlc</groupId>
-            <artifactId>xgboost4j</artifactId>
+            <artifactId>xgboost4j_${scala.binary.version}</artifactId>
             <version>0.90</version>
         </dependency>
         <dependency>
diff --git a/jvm-packages/xgboost4j-tester/generate_pom.py b/jvm-packages/xgboost4j-tester/generate_pom.py
index 3f1099c61a24..a1c19d53258d 100644
--- a/jvm-packages/xgboost4j-tester/generate_pom.py
+++ b/jvm-packages/xgboost4j-tester/generate_pom.py
@@ -8,10 +8,10 @@
   <modelVersion>4.0.0</modelVersion>
 
   <groupId>ml.dmlc</groupId>
-  <artifactId>xgboost4j-tester</artifactId>
+  <artifactId>xgboost4j-tester_2.12</artifactId>
   <version>1.0-SNAPSHOT</version>
 
-  <name>xgboost4j-tester</name>
+  <name>xgboost4j-tester_2.12</name>
 
   <properties>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
@@ -51,19 +51,25 @@
     <dependency>
       <groupId>com.typesafe.akka</groupId>
       <artifactId>akka-actor_${{scala.binary.version}}</artifactId>
-      <version>2.3.11</version>
+      <version>2.5.23</version>
       <scope>compile</scope>
     </dependency>
     <dependency>
       <groupId>com.typesafe.akka</groupId>
       <artifactId>akka-testkit_${{scala.binary.version}}</artifactId>
-      <version>2.3.11</version>
+      <version>2.5.23</version>
       <scope>test</scope>
     </dependency>
     <dependency>
       <groupId>org.scalatest</groupId>
       <artifactId>scalatest_${{scala.binary.version}}</artifactId>
-      <version>3.0.0</version>
+      <version>3.0.8</version>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>org.scalactic</groupId>
+      <artifactId>scalactic_${{scala.binary.version}}</artifactId>
+      <version>3.0.8</version>
       <scope>test</scope>
     </dependency>
     <dependency>
@@ -97,12 +103,12 @@
     </dependency>
     <dependency>
       <groupId>ml.dmlc</groupId>
-      <artifactId>xgboost4j</artifactId>
+      <artifactId>xgboost4j_${{scala.binary.version}}</artifactId>
       <version>{xgboost4j_version}</version>
     </dependency>
     <dependency>
       <groupId>ml.dmlc</groupId>
-      <artifactId>xgboost4j</artifactId>
+      <artifactId>xgboost4j_${{scala.binary.version}}</artifactId>
       <version>{xgboost4j_version}</version>
       <classifier>tests</classifier>
       <type>test-jar</type>
@@ -110,12 +116,12 @@
     </dependency>
     <dependency>
       <groupId>ml.dmlc</groupId>
-      <artifactId>xgboost4j-spark</artifactId>
+      <artifactId>xgboost4j-spark_${{scala.binary.version}}</artifactId>
       <version>{xgboost4j_version}</version>
     </dependency>
     <dependency>
       <groupId>ml.dmlc</groupId>
-      <artifactId>xgboost4j-example</artifactId>
+      <artifactId>xgboost4j-example_${{scala.binary.version}}</artifactId>
       <version>{xgboost4j_version}</version>
     </dependency>
   </dependencies>
@@ -186,7 +192,7 @@
         <version>2.22.1</version>
         <configuration>
           <dependenciesToScan>
-            <dependency>ml.dmlc:xgboost4j</dependency>
+            <dependency>ml.dmlc:xgboost4j_2.12</dependency>
           </dependenciesToScan>
         </configuration>
       </plugin>
diff --git a/jvm-packages/xgboost4j/pom.xml b/jvm-packages/xgboost4j/pom.xml
index 66045b2a081c..af757e4396fb 100644
--- a/jvm-packages/xgboost4j/pom.xml
+++ b/jvm-packages/xgboost4j/pom.xml
@@ -5,10 +5,10 @@
     <modelVersion>4.0.0</modelVersion>
     <parent>
         <groupId>ml.dmlc</groupId>
-        <artifactId>xgboost-jvm</artifactId>
+        <artifactId>xgboost-jvm_2.12</artifactId>
         <version>0.90</version>
     </parent>
-    <artifactId>xgboost4j</artifactId>
+    <artifactId>xgboost4j_2.12</artifactId>
     <version>0.90</version>
     <packaging>jar</packaging>
 
@@ -22,13 +22,13 @@
         <dependency>
             <groupId>com.typesafe.akka</groupId>
             <artifactId>akka-actor_${scala.binary.version}</artifactId>
-            <version>2.3.11</version>
+            <version>2.5.23</version>
             <scope>compile</scope>
         </dependency>
         <dependency>
             <groupId>com.typesafe.akka</groupId>
             <artifactId>akka-testkit_${scala.binary.version}</artifactId>
-            <version>2.3.11</version>
+            <version>2.5.23</version>
             <scope>test</scope>
         </dependency>
     </dependencies>
diff --git a/jvm-packages/xgboost4j/src/main/java/ml/dmlc/xgboost4j/java/DMatrix.java b/jvm-packages/xgboost4j/src/main/java/ml/dmlc/xgboost4j/java/DMatrix.java
index 4d8a49dba751..c62814717d2e 100644
--- a/jvm-packages/xgboost4j/src/main/java/ml/dmlc/xgboost4j/java/DMatrix.java
+++ b/jvm-packages/xgboost4j/src/main/java/ml/dmlc/xgboost4j/java/DMatrix.java
@@ -78,7 +78,8 @@ public DMatrix(String dataPath) throws XGBoostError {
    * @throws XGBoostError
    */
   @Deprecated
-  public DMatrix(long[] headers, int[] indices, float[] data, SparseType st) throws XGBoostError {
+  public DMatrix(long[] headers, int[] indices, float[] data, DMatrix.SparseType st)
+      throws XGBoostError {
     long[] out = new long[1];
     if (st == SparseType.CSR) {
       XGBoostJNI.checkCall(XGBoostJNI.XGDMatrixCreateFromCSREx(headers, indices, data, 0, out));
@@ -100,7 +101,7 @@ public DMatrix(long[] headers, int[] indices, float[] data, SparseType st) throw
    *                     row number
    * @throws XGBoostError
    */
-  public DMatrix(long[] headers, int[] indices, float[] data, SparseType st, int shapeParam)
+  public DMatrix(long[] headers, int[] indices, float[] data, DMatrix.SparseType st, int shapeParam)
           throws XGBoostError {
     long[] out = new long[1];
     if (st == SparseType.CSR) {
diff --git a/jvm-packages/xgboost4j/src/main/scala/ml/dmlc/xgboost4j/scala/rabit/RabitTracker.scala b/jvm-packages/xgboost4j/src/main/scala/ml/dmlc/xgboost4j/scala/rabit/RabitTracker.scala
index 36ad18bb8ef9..fb388d083282 100644
--- a/jvm-packages/xgboost4j/src/main/scala/ml/dmlc/xgboost4j/scala/rabit/RabitTracker.scala
+++ b/jvm-packages/xgboost4j/src/main/scala/ml/dmlc/xgboost4j/scala/rabit/RabitTracker.scala
@@ -131,9 +131,7 @@ private[scala] class RabitTracker(numWorkers: Int, port: Option[Int] = None,
   }
 
   def stop(): Unit = {
-    if (!system.isTerminated) {
-      system.shutdown()
-    }
+    system.terminate()
   }
 
   /**
@@ -170,12 +168,10 @@ private[scala] class RabitTracker(numWorkers: Int, port: Option[Int] = None,
           case Failure(e) =>
             IRabitTracker.TrackerStatus.FAILURE.getStatusCode
         }
-        system.shutdown()
+        system.terminate()
         statusCode
       case Failure(ex: Throwable) =>
-        if (!system.isTerminated) {
-          system.shutdown()
-        }
+        system.terminate()
         IRabitTracker.TrackerStatus.FAILURE.getStatusCode
     }
   }
diff --git a/tests/ci_build/Dockerfile.jvm_cross b/tests/ci_build/Dockerfile.jvm_cross
index aeb44ff82cd0..db47fe33a2fa 100644
--- a/tests/ci_build/Dockerfile.jvm_cross
+++ b/tests/ci_build/Dockerfile.jvm_cross
@@ -15,14 +15,16 @@ RUN \
     # Python
     wget https://repo.continuum.io/miniconda/Miniconda3-4.5.12-Linux-x86_64.sh && \
     bash Miniconda3-4.5.12-Linux-x86_64.sh -b -p /opt/python && \
+    /opt/python/bin/pip install awscli && \
     # Maven
     wget http://apache.osuosl.org/maven/maven-3/3.6.1/binaries/apache-maven-3.6.1-bin.tar.gz && \
     tar xvf apache-maven-3.6.1-bin.tar.gz -C /opt && \
     ln -s /opt/apache-maven-3.6.1/ /opt/maven && \
     # Spark
-    wget https://archive.apache.org/dist/spark/spark-$SPARK_VERSION/spark-$SPARK_VERSION-bin-hadoop2.7.tgz && \
-    tar xvf spark-$SPARK_VERSION-bin-hadoop2.7.tgz -C /opt && \
-    ln -s /opt/spark-$SPARK_VERSION-bin-hadoop2.7 /opt/spark
+    # This should be: wget https://archive.apache.org/dist/spark/spark-$SPARK_VERSION/spark-$SPARK_VERSION-bin-scala2.12-hadoop2.7.tgz
+    /opt/python/bin/python -m awscli s3 cp s3://xgboost-ci-jenkins-artifacts/spark-$SPARK_VERSION-bin-scala2.12-hadoop2.7.tgz . && \
+    tar xvf spark-$SPARK_VERSION-bin-scala2.12-hadoop2.7.tgz -C /opt && \
+    ln -s /opt/spark-$SPARK_VERSION-bin-scala2.12-hadoop2.7 /opt/spark
 
 ENV PATH=/opt/python/bin:/opt/spark/bin:/opt/maven/bin:$PATH
 
diff --git a/tests/ci_build/test_jvm_cross.sh b/tests/ci_build/test_jvm_cross.sh
index 9a9f35011665..378846d651db 100755
--- a/tests/ci_build/test_jvm_cross.sh
+++ b/tests/ci_build/test_jvm_cross.sh
@@ -16,10 +16,10 @@ scala_version=$(mvn help:evaluate -Dexpression=scala.version -q -DforceStdout)
 scala_binary_version=$(mvn help:evaluate -Dexpression=scala.binary.version -q -DforceStdout)
 
 # Install XGBoost4J JAR into local Maven repository
-mvn --no-transfer-progress install:install-file -Dfile=./xgboost4j/target/xgboost4j-${xgboost4j_version}.jar -DgroupId=ml.dmlc -DartifactId=xgboost4j -Dversion=${xgboost4j_version} -Dpackaging=jar
-mvn --no-transfer-progress install:install-file -Dfile=./xgboost4j/target/xgboost4j-${xgboost4j_version}-tests.jar -DgroupId=ml.dmlc -DartifactId=xgboost4j -Dversion=${xgboost4j_version} -Dpackaging=test-jar -Dclassifier=tests
-mvn --no-transfer-progress install:install-file -Dfile=./xgboost4j-spark/target/xgboost4j-spark-${xgboost4j_version}.jar -DgroupId=ml.dmlc -DartifactId=xgboost4j-spark -Dversion=${xgboost4j_version} -Dpackaging=jar
-mvn --no-transfer-progress install:install-file -Dfile=./xgboost4j-example/target/xgboost4j-example-${xgboost4j_version}.jar -DgroupId=ml.dmlc -DartifactId=xgboost4j-example -Dversion=${xgboost4j_version} -Dpackaging=jar
+mvn --no-transfer-progress install:install-file -Dfile=./xgboost4j/target/xgboost4j_${scala_binary_version}-${xgboost4j_version}.jar -DgroupId=ml.dmlc -DartifactId=xgboost4j_${scala_binary_version} -Dversion=${xgboost4j_version} -Dpackaging=jar
+mvn --no-transfer-progress install:install-file -Dfile=./xgboost4j/target/xgboost4j_${scala_binary_version}-${xgboost4j_version}-tests.jar -DgroupId=ml.dmlc -DartifactId=xgboost4j_${scala_binary_version} -Dversion=${xgboost4j_version} -Dpackaging=test-jar -Dclassifier=tests
+mvn --no-transfer-progress install:install-file -Dfile=./xgboost4j-spark/target/xgboost4j-spark_${scala_binary_version}-${xgboost4j_version}.jar -DgroupId=ml.dmlc -DartifactId=xgboost4j-spark_${scala_binary_version} -Dversion=${xgboost4j_version} -Dpackaging=jar
+mvn --no-transfer-progress install:install-file -Dfile=./xgboost4j-example/target/xgboost4j-example_${scala_binary_version}-${xgboost4j_version}.jar -DgroupId=ml.dmlc -DartifactId=xgboost4j-example_${scala_binary_version} -Dversion=${xgboost4j_version} -Dpackaging=jar
 
 cd xgboost4j-tester
 # Generate pom.xml for XGBoost4J-tester, a dummy project to run XGBoost4J tests
@@ -28,14 +28,14 @@ python3 ./generate_pom.py ${xgboost4j_version} ${maven_compiler_source} ${maven_
 mvn --no-transfer-progress package
 
 # Run integration tests with XGBoost4J
-java -jar ./target/xgboost4j-tester-1.0-SNAPSHOT-jar-with-dependencies.jar
+java -jar ./target/xgboost4j-tester_${scala_binary_version}-1.0-SNAPSHOT-jar-with-dependencies.jar
 
 # Run integration tests with XGBoost4J-Spark
 if [ ! -z "$RUN_INTEGRATION_TEST" ]
 then
   python3 get_iris.py
-  spark-submit --class ml.dmlc.xgboost4j.scala.example.spark.SparkTraining --master 'local[8]' ./target/xgboost4j-tester-1.0-SNAPSHOT-jar-with-dependencies.jar ${PWD}/iris.csv
-  spark-submit --class ml.dmlc.xgboost4j.scala.example.spark.SparkMLlibPipeline --master 'local[8]' ./target/xgboost4j-tester-1.0-SNAPSHOT-jar-with-dependencies.jar ${PWD}/iris.csv ${PWD}/native_model ${PWD}/pipeline_model
+  spark-submit --class ml.dmlc.xgboost4j.scala.example.spark.SparkTraining --master 'local[8]' ./target/xgboost4j-tester_${scala_binary_version}-1.0-SNAPSHOT-jar-with-dependencies.jar ${PWD}/iris.csv
+  spark-submit --class ml.dmlc.xgboost4j.scala.example.spark.SparkMLlibPipeline --master 'local[8]' ./target/xgboost4j-tester_${scala_binary_version}-1.0-SNAPSHOT-jar-with-dependencies.jar ${PWD}/iris.csv ${PWD}/native_model ${PWD}/pipeline_model
 fi
 
 set +x