diff --git a/jvm-packages/checkstyle-suppressions.xml b/jvm-packages/checkstyle-suppressions.xml
index da60508fc..28aed4fab 100644
--- a/jvm-packages/checkstyle-suppressions.xml
+++ b/jvm-packages/checkstyle-suppressions.xml
@@ -29,5 +29,5 @@
 
 <suppressions>
 <suppress checks=".*"
-	files="xgboost4j/src/main/java/ml/dmlc/xgboost4j/java/XgboostJNI.java"/>
+	files="xgboost4j/src/main/java/ml/dmlc/xgboost4j/java/XGBoostJNI.java"/>
 </suppressions>
diff --git a/jvm-packages/xgboost4j-demo/src/main/java/ml/dmlc/xgboost4j/java/demo/CustomObjective.java b/jvm-packages/xgboost4j-demo/src/main/java/ml/dmlc/xgboost4j/java/demo/CustomObjective.java
index 8da76b08d..fecc5f687 100644
--- a/jvm-packages/xgboost4j-demo/src/main/java/ml/dmlc/xgboost4j/java/demo/CustomObjective.java
+++ b/jvm-packages/xgboost4j-demo/src/main/java/ml/dmlc/xgboost4j/java/demo/CustomObjective.java
@@ -19,10 +19,11 @@ import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 
-import ml.dmlc.xgboost4j.java.*;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
+import ml.dmlc.xgboost4j.java.*;
+
 /**
  * an example user define objective and eval
  * NOTE: when you do customized loss function, the default prediction value is margin
diff --git a/jvm-packages/xgboost4j-demo/src/main/java/ml/dmlc/xgboost4j/java/demo/DistTrain.java b/jvm-packages/xgboost4j-demo/src/main/java/ml/dmlc/xgboost4j/java/demo/DistTrain.java
index fdc2c1cd8..89c9bcdb0 100644
--- a/jvm-packages/xgboost4j-demo/src/main/java/ml/dmlc/xgboost4j/java/demo/DistTrain.java
+++ b/jvm-packages/xgboost4j-demo/src/main/java/ml/dmlc/xgboost4j/java/demo/DistTrain.java
@@ -4,10 +4,10 @@ import java.io.IOException;
 import java.util.HashMap;
 import java.util.Map;
 
-import ml.dmlc.xgboost4j.java.*;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
+import ml.dmlc.xgboost4j.java.*;
 
 /**
  * Distributed training example, used to quick test distributed training.
diff --git a/jvm-packages/xgboost4j-flink/src/main/scala/ml/dmlc/xgboost4j/flink/Test.scala b/jvm-packages/xgboost4j-flink/src/main/scala/ml/dmlc/xgboost4j/flink/Test.scala
index 15ecd7308..f4934fc2f 100644
--- a/jvm-packages/xgboost4j-flink/src/main/scala/ml/dmlc/xgboost4j/flink/Test.scala
+++ b/jvm-packages/xgboost4j-flink/src/main/scala/ml/dmlc/xgboost4j/flink/Test.scala
@@ -16,7 +16,8 @@
 
 package ml.dmlc.xgboost4j.flink
 
-import ml.dmlc.xgboost4j.java.{RabitTracker, Rabit}
+import ml.dmlc.xgboost4j.java.{Rabit,RabitTracker}
+
 import ml.dmlc.xgboost4j.scala.Booster
 import ml.dmlc.xgboost4j.scala.DMatrix
 import ml.dmlc.xgboost4j.scala.XGBoost
@@ -34,7 +35,7 @@ class ScalaMapFunction(workerEnvs: java.util.Map[String, String])
   extends RichMapPartitionFunction[LabeledVector, Booster] {
   val log = LogFactory.getLog(this.getClass)
   def mapPartition(it : java.lang.Iterable[LabeledVector], collector: Collector[Booster]): Unit = {
-    workerEnvs.put("DMLC_TASK_ID", this.getRuntimeContext.getTaskName)
+    workerEnvs.put("DMLC_TASK_ID", String.valueOf(this.getRuntimeContext.getIndexOfThisSubtask))
     log.info("start with env" + workerEnvs.toString)
     Rabit.init(workerEnvs)
 
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 d8e1aaf4d..a5a9b4972 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
@@ -65,7 +65,7 @@ public class DMatrix {
       logger.info(e.toString());
     }
     long[] out = new long[1];
-    JNIErrorHandle.checkCall(XgboostJNI.XGDMatrixCreateFromDataIter(iter, cache_info, out));
+    JNIErrorHandle.checkCall(XGBoostJNI.XGDMatrixCreateFromDataIter(iter, cache_info, out));
     handle = out[0];
   }
 
@@ -80,7 +80,7 @@ public class DMatrix {
       throw new NullPointerException("dataPath: null");
     }
     long[] out = new long[1];
-    JNIErrorHandle.checkCall(XgboostJNI.XGDMatrixCreateFromFile(dataPath, 1, out));
+    JNIErrorHandle.checkCall(XGBoostJNI.XGDMatrixCreateFromFile(dataPath, 1, out));
     handle = out[0];
   }
 
@@ -95,9 +95,9 @@ public class DMatrix {
   public DMatrix(long[] headers, int[] indices, float[] data, SparseType st) throws XGBoostError {
     long[] out = new long[1];
     if (st == SparseType.CSR) {
-      JNIErrorHandle.checkCall(XgboostJNI.XGDMatrixCreateFromCSR(headers, indices, data, out));
+      JNIErrorHandle.checkCall(XGBoostJNI.XGDMatrixCreateFromCSR(headers, indices, data, out));
     } else if (st == SparseType.CSC) {
-      JNIErrorHandle.checkCall(XgboostJNI.XGDMatrixCreateFromCSC(headers, indices, data, out));
+      JNIErrorHandle.checkCall(XGBoostJNI.XGDMatrixCreateFromCSC(headers, indices, data, out));
     } else {
       throw new UnknownError("unknow sparsetype");
     }
@@ -114,7 +114,7 @@ public class DMatrix {
    */
   public DMatrix(float[] data, int nrow, int ncol) throws XGBoostError {
     long[] out = new long[1];
-    JNIErrorHandle.checkCall(XgboostJNI.XGDMatrixCreateFromMat(data, nrow, ncol, 0.0f, out));
+    JNIErrorHandle.checkCall(XGBoostJNI.XGDMatrixCreateFromMat(data, nrow, ncol, 0.0f, out));
     handle = out[0];
   }
 
@@ -133,7 +133,7 @@ public class DMatrix {
    * @throws XGBoostError native error
    */
   public void setLabel(float[] labels) throws XGBoostError {
-    JNIErrorHandle.checkCall(XgboostJNI.XGDMatrixSetFloatInfo(handle, "label", labels));
+    JNIErrorHandle.checkCall(XGBoostJNI.XGDMatrixSetFloatInfo(handle, "label", labels));
   }
 
   /**
@@ -143,7 +143,7 @@ public class DMatrix {
    * @throws XGBoostError native error
    */
   public void setWeight(float[] weights) throws XGBoostError {
-    JNIErrorHandle.checkCall(XgboostJNI.XGDMatrixSetFloatInfo(handle, "weight", weights));
+    JNIErrorHandle.checkCall(XGBoostJNI.XGDMatrixSetFloatInfo(handle, "weight", weights));
   }
 
   /**
@@ -154,7 +154,7 @@ public class DMatrix {
    * @throws XGBoostError native error
    */
   public void setBaseMargin(float[] baseMargin) throws XGBoostError {
-    JNIErrorHandle.checkCall(XgboostJNI.XGDMatrixSetFloatInfo(handle, "base_margin", baseMargin));
+    JNIErrorHandle.checkCall(XGBoostJNI.XGDMatrixSetFloatInfo(handle, "base_margin", baseMargin));
   }
 
   /**
@@ -176,18 +176,18 @@ public class DMatrix {
    * @throws XGBoostError native error
    */
   public void setGroup(int[] group) throws XGBoostError {
-    JNIErrorHandle.checkCall(XgboostJNI.XGDMatrixSetGroup(handle, group));
+    JNIErrorHandle.checkCall(XGBoostJNI.XGDMatrixSetGroup(handle, group));
   }
 
   private float[] getFloatInfo(String field) throws XGBoostError {
     float[][] infos = new float[1][];
-    JNIErrorHandle.checkCall(XgboostJNI.XGDMatrixGetFloatInfo(handle, field, infos));
+    JNIErrorHandle.checkCall(XGBoostJNI.XGDMatrixGetFloatInfo(handle, field, infos));
     return infos[0];
   }
 
   private int[] getIntInfo(String field) throws XGBoostError {
     int[][] infos = new int[1][];
-    JNIErrorHandle.checkCall(XgboostJNI.XGDMatrixGetUIntInfo(handle, field, infos));
+    JNIErrorHandle.checkCall(XGBoostJNI.XGDMatrixGetUIntInfo(handle, field, infos));
     return infos[0];
   }
 
@@ -230,7 +230,7 @@ public class DMatrix {
    */
   public DMatrix slice(int[] rowIndex) throws XGBoostError {
     long[] out = new long[1];
-    JNIErrorHandle.checkCall(XgboostJNI.XGDMatrixSliceDMatrix(handle, rowIndex, out));
+    JNIErrorHandle.checkCall(XGBoostJNI.XGDMatrixSliceDMatrix(handle, rowIndex, out));
     long sHandle = out[0];
     DMatrix sMatrix = new DMatrix(sHandle);
     return sMatrix;
@@ -244,7 +244,7 @@ public class DMatrix {
    */
   public long rowNum() throws XGBoostError {
     long[] rowNum = new long[1];
-    JNIErrorHandle.checkCall(XgboostJNI.XGDMatrixNumRow(handle, rowNum));
+    JNIErrorHandle.checkCall(XGBoostJNI.XGDMatrixNumRow(handle, rowNum));
     return rowNum[0];
   }
 
@@ -252,7 +252,7 @@ public class DMatrix {
    * save DMatrix to filePath
    */
   public void saveBinary(String filePath) {
-    XgboostJNI.XGDMatrixSaveBinary(handle, filePath, 1);
+    XGBoostJNI.XGDMatrixSaveBinary(handle, filePath, 1);
   }
 
   /**
@@ -285,7 +285,7 @@ public class DMatrix {
 
   public synchronized void dispose() {
     if (handle != 0) {
-      XgboostJNI.XGDMatrixFree(handle);
+      XGBoostJNI.XGDMatrixFree(handle);
       handle = 0;
     }
   }
diff --git a/jvm-packages/xgboost4j/src/main/java/ml/dmlc/xgboost4j/java/JNIErrorHandle.java b/jvm-packages/xgboost4j/src/main/java/ml/dmlc/xgboost4j/java/JNIErrorHandle.java
index 7bd64c149..bb64ee56f 100644
--- a/jvm-packages/xgboost4j/src/main/java/ml/dmlc/xgboost4j/java/JNIErrorHandle.java
+++ b/jvm-packages/xgboost4j/src/main/java/ml/dmlc/xgboost4j/java/JNIErrorHandle.java
@@ -45,7 +45,7 @@ class JNIErrorHandle {
    */
   static void checkCall(int ret) throws XGBoostError {
     if (ret != 0) {
-      throw new XGBoostError(XgboostJNI.XGBGetLastError());
+      throw new XGBoostError(XGBoostJNI.XGBGetLastError());
     }
   }
 
diff --git a/jvm-packages/xgboost4j/src/main/java/ml/dmlc/xgboost4j/java/JavaBoosterImpl.java b/jvm-packages/xgboost4j/src/main/java/ml/dmlc/xgboost4j/java/JavaBoosterImpl.java
index 7e2ade607..37860dc6f 100644
--- a/jvm-packages/xgboost4j/src/main/java/ml/dmlc/xgboost4j/java/JavaBoosterImpl.java
+++ b/jvm-packages/xgboost4j/src/main/java/ml/dmlc/xgboost4j/java/JavaBoosterImpl.java
@@ -81,7 +81,7 @@ class JavaBoosterImpl implements Booster {
       handles = dmatrixsToHandles(dMatrixs);
     }
     long[] out = new long[1];
-    JNIErrorHandle.checkCall(XgboostJNI.XGBoosterCreate(handles, out));
+    JNIErrorHandle.checkCall(XGBoostJNI.XGBoosterCreate(handles, out));
 
     handle = out[0];
   }
@@ -94,7 +94,7 @@ class JavaBoosterImpl implements Booster {
    * @throws XGBoostError native error
    */
   public final void setParam(String key, String value) throws XGBoostError {
-    JNIErrorHandle.checkCall(XgboostJNI.XGBoosterSetParam(handle, key, value));
+    JNIErrorHandle.checkCall(XGBoostJNI.XGBoosterSetParam(handle, key, value));
   }
 
   /**
@@ -120,7 +120,7 @@ class JavaBoosterImpl implements Booster {
    * @throws XGBoostError native error
    */
   public void update(DMatrix dtrain, int iter) throws XGBoostError {
-    JNIErrorHandle.checkCall(XgboostJNI.XGBoosterUpdateOneIter(handle, iter, dtrain.getHandle()));
+    JNIErrorHandle.checkCall(XGBoostJNI.XGBoosterUpdateOneIter(handle, iter, dtrain.getHandle()));
   }
 
   /**
@@ -149,7 +149,7 @@ class JavaBoosterImpl implements Booster {
       throw new AssertionError(String.format("grad/hess length mismatch %s / %s", grad.length,
               hess.length));
     }
-    JNIErrorHandle.checkCall(XgboostJNI.XGBoosterBoostOneIter(handle, dtrain.getHandle(), grad,
+    JNIErrorHandle.checkCall(XGBoostJNI.XGBoosterBoostOneIter(handle, dtrain.getHandle(), grad,
             hess));
   }
 
@@ -165,7 +165,7 @@ class JavaBoosterImpl implements Booster {
   public String evalSet(DMatrix[] evalMatrixs, String[] evalNames, int iter) throws XGBoostError {
     long[] handles = dmatrixsToHandles(evalMatrixs);
     String[] evalInfo = new String[1];
-    JNIErrorHandle.checkCall(XgboostJNI.XGBoosterEvalOneIter(handle, iter, handles, evalNames,
+    JNIErrorHandle.checkCall(XGBoostJNI.XGBoosterEvalOneIter(handle, iter, handles, evalNames,
             evalInfo));
     return evalInfo[0];
   }
@@ -211,7 +211,7 @@ class JavaBoosterImpl implements Booster {
       optionMask = 2;
     }
     float[][] rawPredicts = new float[1][];
-    JNIErrorHandle.checkCall(XgboostJNI.XGBoosterPredict(handle, data.getHandle(), optionMask,
+    JNIErrorHandle.checkCall(XGBoostJNI.XGBoosterPredict(handle, data.getHandle(), optionMask,
             treeLimit, rawPredicts));
     int row = (int) data.rowNum();
     int col = rawPredicts[0].length / row;
@@ -284,11 +284,11 @@ class JavaBoosterImpl implements Booster {
    * @param modelPath model path
    */
   public void saveModel(String modelPath) throws XGBoostError{
-    JNIErrorHandle.checkCall(XgboostJNI.XGBoosterSaveModel(handle, modelPath));
+    JNIErrorHandle.checkCall(XGBoostJNI.XGBoosterSaveModel(handle, modelPath));
   }
 
   private void loadModel(String modelPath) {
-    XgboostJNI.XGBoosterLoadModel(handle, modelPath);
+    XGBoostJNI.XGBoosterLoadModel(handle, modelPath);
   }
 
   /**
@@ -304,7 +304,7 @@ class JavaBoosterImpl implements Booster {
       statsFlag = 1;
     }
     String[][] modelInfos = new String[1][];
-    JNIErrorHandle.checkCall(XgboostJNI.XGBoosterDumpModel(handle, "", statsFlag, modelInfos));
+    JNIErrorHandle.checkCall(XGBoostJNI.XGBoosterDumpModel(handle, "", statsFlag, modelInfos));
     return modelInfos[0];
   }
 
@@ -322,7 +322,7 @@ class JavaBoosterImpl implements Booster {
       statsFlag = 1;
     }
     String[][] modelInfos = new String[1][];
-    JNIErrorHandle.checkCall(XgboostJNI.XGBoosterDumpModel(handle, featureMap, statsFlag,
+    JNIErrorHandle.checkCall(XGBoostJNI.XGBoosterDumpModel(handle, featureMap, statsFlag,
             modelInfos));
     return modelInfos[0];
   }
@@ -450,7 +450,7 @@ class JavaBoosterImpl implements Booster {
    */
   public byte[] toByteArray() throws XGBoostError {
     byte[][] bytes = new byte[1][];
-    JNIErrorHandle.checkCall(XgboostJNI.XGBoosterGetModelRaw(this.handle, bytes));
+    JNIErrorHandle.checkCall(XGBoostJNI.XGBoosterGetModelRaw(this.handle, bytes));
     return bytes[0];
   }
 
@@ -463,7 +463,7 @@ class JavaBoosterImpl implements Booster {
    */
   int loadRabitCheckpoint() throws XGBoostError {
     int[] out = new int[1];
-    JNIErrorHandle.checkCall(XgboostJNI.XGBoosterLoadRabitCheckpoint(this.handle, out));
+    JNIErrorHandle.checkCall(XGBoostJNI.XGBoosterLoadRabitCheckpoint(this.handle, out));
     return out[0];
   }
 
@@ -473,7 +473,7 @@ class JavaBoosterImpl implements Booster {
    * @throws XGBoostError
    */
   void saveRabitCheckpoint() throws XGBoostError {
-    JNIErrorHandle.checkCall(XgboostJNI.XGBoosterSaveRabitCheckpoint(this.handle));
+    JNIErrorHandle.checkCall(XGBoostJNI.XGBoosterSaveRabitCheckpoint(this.handle));
   }
 
   /**
@@ -504,7 +504,7 @@ class JavaBoosterImpl implements Booster {
     try {
       this.init(null);
       byte[] bytes = (byte[])in.readObject();
-      JNIErrorHandle.checkCall(XgboostJNI.XGBoosterLoadModelFromBuffer(this.handle, bytes));
+      JNIErrorHandle.checkCall(XGBoostJNI.XGBoosterLoadModelFromBuffer(this.handle, bytes));
     } catch (XGBoostError ex) {
       throw new IOException(ex.toString());
     }
@@ -518,7 +518,7 @@ class JavaBoosterImpl implements Booster {
 
   public synchronized void dispose() {
     if (handle != 0L) {
-      XgboostJNI.XGBoosterFree(handle);
+      XGBoostJNI.XGBoosterFree(handle);
       handle = 0;
     }
   }
diff --git a/jvm-packages/xgboost4j/src/main/java/ml/dmlc/xgboost4j/java/Rabit.java b/jvm-packages/xgboost4j/src/main/java/ml/dmlc/xgboost4j/java/Rabit.java
index ce4be04c5..d8408d26c 100644
--- a/jvm-packages/xgboost4j/src/main/java/ml/dmlc/xgboost4j/java/Rabit.java
+++ b/jvm-packages/xgboost4j/src/main/java/ml/dmlc/xgboost4j/java/Rabit.java
@@ -23,7 +23,7 @@ public class Rabit {
 
   private static void checkCall(int ret) throws XGBoostError {
     if (ret != 0) {
-      throw new XGBoostError(XgboostJNI.XGBGetLastError());
+      throw new XGBoostError(XGBoostJNI.XGBGetLastError());
     }
   }
 
@@ -38,7 +38,7 @@ public class Rabit {
     for (java.util.Map.Entry<String, String> e : envs.entrySet()) {
       args[idx++] = e.getKey() + '=' + e.getValue();
     }
-    checkCall(XgboostJNI.RabitInit(args));
+    checkCall(XGBoostJNI.RabitInit(args));
   }
 
   /**
@@ -46,7 +46,7 @@ public class Rabit {
    * @throws XGBoostError
    */
   public static void shutdown() throws XGBoostError {
-    checkCall(XgboostJNI.RabitFinalize());
+    checkCall(XGBoostJNI.RabitFinalize());
   }
 
   /**
@@ -55,7 +55,7 @@ public class Rabit {
    * @throws XGBoostError
    */
   public static void trackerPrint(String msg) throws XGBoostError {
-    checkCall(XgboostJNI.RabitTrackerPrint(msg));
+    checkCall(XGBoostJNI.RabitTrackerPrint(msg));
   }
 
   /**
@@ -66,7 +66,7 @@ public class Rabit {
    */
   public static int versionNumber() throws XGBoostError {
     int[] out = new int[1];
-    checkCall(XgboostJNI.RabitVersionNumber(out));
+    checkCall(XGBoostJNI.RabitVersionNumber(out));
     return out[0];
   }
 
@@ -77,7 +77,7 @@ public class Rabit {
    */
   public static int getRank() throws XGBoostError {
     int[] out = new int[1];
-    checkCall(XgboostJNI.RabitGetRank(out));
+    checkCall(XGBoostJNI.RabitGetRank(out));
     return out[0];
   }
 
@@ -88,7 +88,7 @@ public class Rabit {
    */
   public static int getWorldSize() throws XGBoostError {
     int[] out = new int[1];
-    checkCall(XgboostJNI.RabitGetWorldSize(out));
+    checkCall(XGBoostJNI.RabitGetWorldSize(out));
     return out[0];
   }
 }
diff --git a/jvm-packages/xgboost4j/src/main/java/ml/dmlc/xgboost4j/java/XgboostJNI.java b/jvm-packages/xgboost4j/src/main/java/ml/dmlc/xgboost4j/java/XgboostJNI.java
index 9f6a15a9c..29ea29163 100644
--- a/jvm-packages/xgboost4j/src/main/java/ml/dmlc/xgboost4j/java/XgboostJNI.java
+++ b/jvm-packages/xgboost4j/src/main/java/ml/dmlc/xgboost4j/java/XgboostJNI.java
@@ -22,7 +22,7 @@ package ml.dmlc.xgboost4j.java;
  *
  * @author hzx
  */
-class XgboostJNI {
+class XGBoostJNI {
   public final static native String XGBGetLastError();
 
   public final static native int XGDMatrixCreateFromFile(String fname, int silent, long[] out);
diff --git a/jvm-packages/xgboost4j/src/main/scala/ml/dmlc/xgboost4j/scala/DMatrix.scala b/jvm-packages/xgboost4j/src/main/scala/ml/dmlc/xgboost4j/scala/DMatrix.scala
index 4ee8d04fe..c62784c08 100644
--- a/jvm-packages/xgboost4j/src/main/scala/ml/dmlc/xgboost4j/scala/DMatrix.scala
+++ b/jvm-packages/xgboost4j/src/main/scala/ml/dmlc/xgboost4j/scala/DMatrix.scala
@@ -21,7 +21,6 @@ import _root_.scala.collection.JavaConverters._
 import ml.dmlc.xgboost4j.java.{DMatrix => JDMatrix, DataBatch, XGBoostError}
 
 class DMatrix private[scala](private[scala] val jDMatrix: JDMatrix) {
-
   /**
    * init DMatrix from file (svmlight format)
    *
diff --git a/jvm-packages/xgboost4j/src/main/scala/ml/dmlc/xgboost4j/scala/ObjectiveTrait.scala b/jvm-packages/xgboost4j/src/main/scala/ml/dmlc/xgboost4j/scala/ObjectiveTrait.scala
index 1b563f96d..f6d7fd496 100644
--- a/jvm-packages/xgboost4j/src/main/scala/ml/dmlc/xgboost4j/scala/ObjectiveTrait.scala
+++ b/jvm-packages/xgboost4j/src/main/scala/ml/dmlc/xgboost4j/scala/ObjectiveTrait.scala
@@ -16,10 +16,11 @@
 
 package ml.dmlc.xgboost4j.scala
 
-import ml.dmlc.xgboost4j.java
-import ml.dmlc.xgboost4j.java.IObjective
 import scala.collection.JavaConverters._
 
+import ml.dmlc.xgboost4j.java.{DMatrix => JDMatrix}
+import ml.dmlc.xgboost4j.java.IObjective
+
 trait ObjectiveTrait extends IObjective {
   /**
    * user define objective function, return gradient and second order gradient
@@ -30,7 +31,7 @@ trait ObjectiveTrait extends IObjective {
    */
   def getGradient(predicts: Array[Array[Float]], dtrain: DMatrix): List[Array[Float]]
 
-  private[scala] def getGradient(predicts: Array[Array[Float]], dtrain: java.DMatrix):
+  private[scala] def getGradient(predicts: Array[Array[Float]], dtrain: JDMatrix):
     java.util.List[Array[Float]] = {
     getGradient(predicts, new DMatrix(dtrain)).asJava
   }
diff --git a/jvm-packages/xgboost4j/src/main/scala/ml/dmlc/xgboost4j/scala/XGBoost.scala b/jvm-packages/xgboost4j/src/main/scala/ml/dmlc/xgboost4j/scala/XGBoost.scala
index 966784d18..58ed51527 100644
--- a/jvm-packages/xgboost4j/src/main/scala/ml/dmlc/xgboost4j/scala/XGBoost.scala
+++ b/jvm-packages/xgboost4j/src/main/scala/ml/dmlc/xgboost4j/scala/XGBoost.scala
@@ -16,6 +16,7 @@
 
 package ml.dmlc.xgboost4j.scala
 
+import ml.dmlc.xgboost4j.java.{XGBoost => JXGBoost}
 import scala.collection.JavaConverters._
 
 object XGBoost {
diff --git a/jvm-packages/xgboost4j/src/native/xgboost4j.cpp b/jvm-packages/xgboost4j/src/native/xgboost4j.cpp
index 1c35c8311..9475bb248 100644
--- a/jvm-packages/xgboost4j/src/native/xgboost4j.cpp
+++ b/jvm-packages/xgboost4j/src/native/xgboost4j.cpp
@@ -134,11 +134,11 @@ XGB_EXTERN_C int XGBoost4jCallbackDataIterNext(
 }
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGBGetLastError
  * Signature: ()Ljava/lang/String;
  */
-JNIEXPORT jstring JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBGetLastError
+JNIEXPORT jstring JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGBGetLastError
   (JNIEnv *jenv, jclass jcls) {
   jstring jresult = 0;
   const char* result = XGBGetLastError();
@@ -149,11 +149,11 @@ JNIEXPORT jstring JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBGetLastError
 }
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGDMatrixCreateFromDataIter
  * Signature: (Ljava/util/Iterator;Ljava/lang/String;[J)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixCreateFromDataIter
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGDMatrixCreateFromDataIter
   (JNIEnv *jenv, jclass jcls, jobject jiter, jstring jcache_info, jlongArray jout) {
   DMatrixHandle result;
   const char* cache_info = nullptr;
@@ -170,11 +170,11 @@ JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixCreateFromData
 }
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGDMatrixCreateFromFile
  * Signature: (Ljava/lang/String;I[J)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixCreateFromFile
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGDMatrixCreateFromFile
   (JNIEnv *jenv, jclass jcls, jstring jfname, jint jsilent, jlongArray jout) {
   DMatrixHandle result;
   const char* fname = jenv->GetStringUTFChars(jfname, 0);
@@ -187,11 +187,11 @@ JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixCreateFromFile
 }
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGDMatrixCreateFromCSR
  * Signature: ([J[J[F)J
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixCreateFromCSR
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGDMatrixCreateFromCSR
   (JNIEnv *jenv, jclass jcls, jlongArray jindptr, jintArray jindices, jfloatArray jdata, jlongArray jout) {
   DMatrixHandle result;
   jlong* indptr = jenv->GetLongArrayElements(jindptr, 0);
@@ -209,11 +209,11 @@ JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixCreateFromCSR
 }
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGDMatrixCreateFromCSC
  * Signature: ([J[J[F)J
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixCreateFromCSC
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGDMatrixCreateFromCSC
   (JNIEnv *jenv, jclass jcls, jlongArray jindptr, jintArray jindices, jfloatArray jdata, jlongArray jout) {
   DMatrixHandle result;
   jlong* indptr = jenv->GetLongArrayElements(jindptr, NULL);
@@ -233,11 +233,11 @@ JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixCreateFromCSC
 }
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGDMatrixCreateFromMat
  * Signature: ([FIIF)J
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixCreateFromMat
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGDMatrixCreateFromMat
   (JNIEnv *jenv, jclass jcls, jfloatArray jdata, jint jnrow, jint jncol, jfloat jmiss, jlongArray jout) {
   DMatrixHandle result;
   jfloat* data = jenv->GetFloatArrayElements(jdata, 0);
@@ -251,11 +251,11 @@ JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixCreateFromMat
 }
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGDMatrixSliceDMatrix
  * Signature: (J[I)J
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixSliceDMatrix
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGDMatrixSliceDMatrix
   (JNIEnv *jenv, jclass jcls, jlong jhandle, jintArray jindexset, jlongArray jout) {
   DMatrixHandle result;
   DMatrixHandle handle = (DMatrixHandle) jhandle;
@@ -272,11 +272,11 @@ JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixSliceDMatrix
 }
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGDMatrixFree
  * Signature: (J)V
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixFree
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGDMatrixFree
   (JNIEnv *jenv, jclass jcls, jlong jhandle) {
   DMatrixHandle handle = (DMatrixHandle) jhandle;
   int ret = XGDMatrixFree(handle);
@@ -284,11 +284,11 @@ JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixFree
 }
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGDMatrixSaveBinary
  * Signature: (JLjava/lang/String;I)V
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixSaveBinary
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGDMatrixSaveBinary
   (JNIEnv *jenv, jclass jcls, jlong jhandle, jstring jfname, jint jsilent) {
   DMatrixHandle handle = (DMatrixHandle) jhandle;
   const char* fname = jenv->GetStringUTFChars(jfname, 0);
@@ -298,11 +298,11 @@ JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixSaveBinary
 }
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGDMatrixSetFloatInfo
  * Signature: (JLjava/lang/String;[F)V
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixSetFloatInfo
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGDMatrixSetFloatInfo
   (JNIEnv *jenv, jclass jcls, jlong jhandle, jstring jfield, jfloatArray jarray) {
   DMatrixHandle handle = (DMatrixHandle) jhandle;
   const char*  field = jenv->GetStringUTFChars(jfield, 0);
@@ -317,11 +317,11 @@ JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixSetFloatInfo
 }
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGDMatrixSetUIntInfo
  * Signature: (JLjava/lang/String;[I)V
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixSetUIntInfo
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGDMatrixSetUIntInfo
   (JNIEnv *jenv, jclass jcls, jlong jhandle, jstring jfield, jintArray jarray) {
   DMatrixHandle handle = (DMatrixHandle) jhandle;
   const char*  field = jenv->GetStringUTFChars(jfield, 0);
@@ -336,11 +336,11 @@ JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixSetUIntInfo
 }
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGDMatrixSetGroup
  * Signature: (J[I)V
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixSetGroup
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGDMatrixSetGroup
   (JNIEnv * jenv, jclass jcls, jlong jhandle, jintArray jarray) {
   DMatrixHandle handle = (DMatrixHandle) jhandle;
   jint* array = jenv->GetIntArrayElements(jarray, NULL);
@@ -352,11 +352,11 @@ JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixSetGroup
 }
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGDMatrixGetFloatInfo
  * Signature: (JLjava/lang/String;)[F
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixGetFloatInfo
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGDMatrixGetFloatInfo
   (JNIEnv *jenv, jclass jcls, jlong jhandle, jstring jfield, jobjectArray jout) {
   DMatrixHandle handle = (DMatrixHandle) jhandle;
   const char*  field = jenv->GetStringUTFChars(jfield, 0);
@@ -374,11 +374,11 @@ JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixGetFloatInfo
 }
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGDMatrixGetUIntInfo
  * Signature: (JLjava/lang/String;)[I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixGetUIntInfo
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGDMatrixGetUIntInfo
   (JNIEnv *jenv, jclass jcls, jlong jhandle, jstring jfield, jobjectArray jout) {
   DMatrixHandle handle = (DMatrixHandle) jhandle;
   const char*  field = jenv->GetStringUTFChars(jfield, 0);
@@ -395,11 +395,11 @@ JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixGetUIntInfo
 }
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGDMatrixNumRow
  * Signature: (J)J
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixNumRow
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGDMatrixNumRow
   (JNIEnv *jenv, jclass jcls, jlong jhandle, jlongArray jout) {
   DMatrixHandle handle = (DMatrixHandle) jhandle;
   bst_ulong result[1];
@@ -409,11 +409,11 @@ JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixNumRow
 }
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGBoosterCreate
  * Signature: ([J)J
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterCreate
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGBoosterCreate
   (JNIEnv *jenv, jclass jcls, jlongArray jhandles, jlongArray jout) {
   std::vector<DMatrixHandle> handles;
   if (jhandles != nullptr) {
@@ -431,11 +431,11 @@ JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterCreate
 }
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGBoosterFree
  * Signature: (J)V
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterFree
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGBoosterFree
   (JNIEnv *jenv, jclass jcls, jlong jhandle) {
     BoosterHandle handle = (BoosterHandle) jhandle;
     return XGBoosterFree(handle);
@@ -443,11 +443,11 @@ JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterFree
 
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGBoosterSetParam
  * Signature: (JLjava/lang/String;Ljava/lang/String;)V
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterSetParam
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGBoosterSetParam
   (JNIEnv *jenv, jclass jcls, jlong jhandle, jstring jname, jstring jvalue) {
   BoosterHandle handle = (BoosterHandle) jhandle;
   const char* name = jenv->GetStringUTFChars(jname, 0);
@@ -460,11 +460,11 @@ JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterSetParam
 }
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGBoosterUpdateOneIter
  * Signature: (JIJ)V
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterUpdateOneIter
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGBoosterUpdateOneIter
   (JNIEnv *jenv, jclass jcls, jlong jhandle, jint jiter, jlong jdtrain) {
   BoosterHandle handle = (BoosterHandle) jhandle;
   DMatrixHandle dtrain = (DMatrixHandle) jdtrain;
@@ -472,11 +472,11 @@ JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterUpdateOneIter
 }
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGBoosterBoostOneIter
  * Signature: (JJ[F[F)V
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterBoostOneIter
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGBoosterBoostOneIter
   (JNIEnv *jenv, jclass jcls, jlong jhandle, jlong jdtrain, jfloatArray jgrad, jfloatArray jhess) {
   BoosterHandle handle = (BoosterHandle) jhandle;
   DMatrixHandle dtrain = (DMatrixHandle) jdtrain;
@@ -491,11 +491,11 @@ JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterBoostOneIter
 }
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGBoosterEvalOneIter
  * Signature: (JI[J[Ljava/lang/String;)Ljava/lang/String;
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterEvalOneIter
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGBoosterEvalOneIter
   (JNIEnv *jenv, jclass jcls, jlong jhandle, jint jiter, jlongArray jdmats, jobjectArray jevnames, jobjectArray jout) {
   BoosterHandle handle = (BoosterHandle) jhandle;
   std::vector<DMatrixHandle> dmats;
@@ -530,11 +530,11 @@ JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterEvalOneIter
 }
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGBoosterPredict
  * Signature: (JJIJ)[F
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterPredict
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGBoosterPredict
   (JNIEnv *jenv, jclass jcls, jlong jhandle, jlong jdmat, jint joption_mask, jint jntree_limit, jobjectArray jout) {
   BoosterHandle handle = (BoosterHandle) jhandle;
   DMatrixHandle dmat = (DMatrixHandle) jdmat;
@@ -550,11 +550,11 @@ JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterPredict
 }
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGBoosterLoadModel
  * Signature: (JLjava/lang/String;)V
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterLoadModel
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGBoosterLoadModel
   (JNIEnv *jenv, jclass jcls, jlong jhandle, jstring jfname) {
   BoosterHandle handle = (BoosterHandle) jhandle;
   const char* fname = jenv->GetStringUTFChars(jfname, 0);
@@ -565,11 +565,11 @@ JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterLoadModel
 }
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGBoosterSaveModel
  * Signature: (JLjava/lang/String;)V
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterSaveModel
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGBoosterSaveModel
   (JNIEnv *jenv, jclass jcls, jlong jhandle, jstring jfname) {
   BoosterHandle handle = (BoosterHandle) jhandle;
   const char*  fname = jenv->GetStringUTFChars(jfname, 0);
@@ -580,11 +580,11 @@ JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterSaveModel
 }
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGBoosterLoadModelFromBuffer
  * Signature: (J[B)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterLoadModelFromBuffer
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGBoosterLoadModelFromBuffer
     (JNIEnv *jenv, jclass jcls, jlong jhandle, jbyteArray jbytes) {
   BoosterHandle handle = (BoosterHandle) jhandle;
   jbyte* buffer = jenv->GetByteArrayElements(jbytes, 0);
@@ -595,11 +595,11 @@ JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterLoadModelFromB
 }
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGBoosterGetModelRaw
  * Signature: (J[[B)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterGetModelRaw
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGBoosterGetModelRaw
   (JNIEnv * jenv, jclass jcls, jlong jhandle, jobjectArray jout) {
   BoosterHandle handle = (BoosterHandle) jhandle;
   bst_ulong len = 0;
@@ -615,11 +615,11 @@ JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterGetModelRaw
 }
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGBoosterDumpModel
  * Signature: (JLjava/lang/String;I)[Ljava/lang/String;
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterDumpModel
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGBoosterDumpModel
   (JNIEnv *jenv, jclass jcls, jlong jhandle, jstring jfmap, jint jwith_stats, jobjectArray jout) {
   BoosterHandle handle = (BoosterHandle) jhandle;
   const char *fmap = jenv->GetStringUTFChars(jfmap, 0);
@@ -640,11 +640,11 @@ JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterDumpModel
 }
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGBoosterLoadRabitCheckpoint
  * Signature: (J[I)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterLoadRabitCheckpoint
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGBoosterLoadRabitCheckpoint
   (JNIEnv *jenv , jclass jcls, jlong jhandle, jintArray jout) {
   BoosterHandle handle = (BoosterHandle) jhandle;
   int version;
@@ -654,22 +654,22 @@ JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterLoadRabitCheck
 }
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGBoosterSaveRabitCheckpoint
  * Signature: (J)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterSaveRabitCheckpoint
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGBoosterSaveRabitCheckpoint
   (JNIEnv *jenv, jclass jcls, jlong jhandle) {
   BoosterHandle handle = (BoosterHandle) jhandle;
   return XGBoosterSaveRabitCheckpoint(handle);
 }
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    RabitInit
  * Signature: ([Ljava/lang/String;)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_RabitInit
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_RabitInit
   (JNIEnv *jenv, jclass jcls, jobjectArray jargs) {
   std::vector<std::string> args;
   std::vector<char*> argv;
@@ -691,22 +691,22 @@ JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_RabitInit
 }
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    RabitFinalize
  * Signature: ()I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_RabitFinalize
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_RabitFinalize
   (JNIEnv *jenv, jclass jcls) {
   RabitFinalize();
   return 0;
 }
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    RabitTrackerPrint
  * Signature: (Ljava/lang/String;)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_RabitTrackerPrint
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_RabitTrackerPrint
   (JNIEnv *jenv, jclass jcls, jstring jmsg) {
   std::string str(jenv->GetStringUTFChars(jmsg, 0),
                   jenv->GetStringLength(jmsg));
@@ -715,11 +715,11 @@ JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_RabitTrackerPrint
 }
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    RabitGetRank
  * Signature: ([I)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_RabitGetRank
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_RabitGetRank
   (JNIEnv *jenv, jclass jcls, jintArray jout) {
   int rank = RabitGetRank();
   jenv->SetIntArrayRegion(jout, 0, 1, &rank);
@@ -727,11 +727,11 @@ JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_RabitGetRank
 }
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    RabitGetWorldSize
  * Signature: ([I)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_RabitGetWorldSize
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_RabitGetWorldSize
   (JNIEnv *jenv, jclass jcls, jintArray jout) {
   int out = RabitGetWorldSize();
   jenv->SetIntArrayRegion(jout, 0, 1, &out);
@@ -739,11 +739,11 @@ JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_RabitGetWorldSize
 }
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    RabitVersionNumber
  * Signature: ([I)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_RabitVersionNumber
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_RabitVersionNumber
   (JNIEnv *jenv, jclass jcls, jintArray jout) {
   int out = RabitVersionNumber();
   jenv->SetIntArrayRegion(jout, 0, 1, &out);
diff --git a/jvm-packages/xgboost4j/src/native/xgboost4j.h b/jvm-packages/xgboost4j/src/native/xgboost4j.h
index 0a3eeae3a..eb2e0244a 100644
--- a/jvm-packages/xgboost4j/src/native/xgboost4j.h
+++ b/jvm-packages/xgboost4j/src/native/xgboost4j.h
@@ -1,306 +1,306 @@
 /* DO NOT EDIT THIS FILE - it is machine generated */
 #include <jni.h>
-/* Header for class ml_dmlc_xgboost4j_XgboostJNI */
+/* Header for class ml_dmlc_xgboost4j_java_XGBoostJNI */
 
-#ifndef _Included_ml_dmlc_xgboost4j_XgboostJNI
-#define _Included_ml_dmlc_xgboost4j_XgboostJNI
+#ifndef _Included_ml_dmlc_xgboost4j_java_XGBoostJNI
+#define _Included_ml_dmlc_xgboost4j_java_XGBoostJNI
 #ifdef __cplusplus
 extern "C" {
 #endif
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGBGetLastError
  * Signature: ()Ljava/lang/String;
  */
-JNIEXPORT jstring JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBGetLastError
+JNIEXPORT jstring JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGBGetLastError
   (JNIEnv *, jclass);
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGDMatrixCreateFromFile
  * Signature: (Ljava/lang/String;I[J)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixCreateFromFile
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGDMatrixCreateFromFile
   (JNIEnv *, jclass, jstring, jint, jlongArray);
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGDMatrixCreateFromDataIter
  * Signature: (Ljava/util/Iterator;Ljava/lang/String;[J)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixCreateFromDataIter
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGDMatrixCreateFromDataIter
   (JNIEnv *, jclass, jobject, jstring, jlongArray);
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGDMatrixCreateFromCSR
  * Signature: ([J[I[F[J)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixCreateFromCSR
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGDMatrixCreateFromCSR
   (JNIEnv *, jclass, jlongArray, jintArray, jfloatArray, jlongArray);
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGDMatrixCreateFromCSC
  * Signature: ([J[I[F[J)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixCreateFromCSC
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGDMatrixCreateFromCSC
   (JNIEnv *, jclass, jlongArray, jintArray, jfloatArray, jlongArray);
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGDMatrixCreateFromMat
  * Signature: ([FIIF[J)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixCreateFromMat
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGDMatrixCreateFromMat
   (JNIEnv *, jclass, jfloatArray, jint, jint, jfloat, jlongArray);
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGDMatrixSliceDMatrix
  * Signature: (J[I[J)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixSliceDMatrix
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGDMatrixSliceDMatrix
   (JNIEnv *, jclass, jlong, jintArray, jlongArray);
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGDMatrixFree
  * Signature: (J)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixFree
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGDMatrixFree
   (JNIEnv *, jclass, jlong);
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGDMatrixSaveBinary
  * Signature: (JLjava/lang/String;I)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixSaveBinary
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGDMatrixSaveBinary
   (JNIEnv *, jclass, jlong, jstring, jint);
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGDMatrixSetFloatInfo
  * Signature: (JLjava/lang/String;[F)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixSetFloatInfo
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGDMatrixSetFloatInfo
   (JNIEnv *, jclass, jlong, jstring, jfloatArray);
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGDMatrixSetUIntInfo
  * Signature: (JLjava/lang/String;[I)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixSetUIntInfo
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGDMatrixSetUIntInfo
   (JNIEnv *, jclass, jlong, jstring, jintArray);
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGDMatrixSetGroup
  * Signature: (J[I)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixSetGroup
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGDMatrixSetGroup
   (JNIEnv *, jclass, jlong, jintArray);
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGDMatrixGetFloatInfo
  * Signature: (JLjava/lang/String;[[F)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixGetFloatInfo
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGDMatrixGetFloatInfo
   (JNIEnv *, jclass, jlong, jstring, jobjectArray);
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGDMatrixGetUIntInfo
  * Signature: (JLjava/lang/String;[[I)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixGetUIntInfo
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGDMatrixGetUIntInfo
   (JNIEnv *, jclass, jlong, jstring, jobjectArray);
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGDMatrixNumRow
  * Signature: (J[J)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGDMatrixNumRow
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGDMatrixNumRow
   (JNIEnv *, jclass, jlong, jlongArray);
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGBoosterCreate
  * Signature: ([J[J)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterCreate
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGBoosterCreate
   (JNIEnv *, jclass, jlongArray, jlongArray);
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGBoosterFree
  * Signature: (J)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterFree
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGBoosterFree
   (JNIEnv *, jclass, jlong);
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGBoosterSetParam
  * Signature: (JLjava/lang/String;Ljava/lang/String;)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterSetParam
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGBoosterSetParam
   (JNIEnv *, jclass, jlong, jstring, jstring);
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGBoosterUpdateOneIter
  * Signature: (JIJ)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterUpdateOneIter
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGBoosterUpdateOneIter
   (JNIEnv *, jclass, jlong, jint, jlong);
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGBoosterBoostOneIter
  * Signature: (JJ[F[F)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterBoostOneIter
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGBoosterBoostOneIter
   (JNIEnv *, jclass, jlong, jlong, jfloatArray, jfloatArray);
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGBoosterEvalOneIter
  * Signature: (JI[J[Ljava/lang/String;[Ljava/lang/String;)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterEvalOneIter
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGBoosterEvalOneIter
   (JNIEnv *, jclass, jlong, jint, jlongArray, jobjectArray, jobjectArray);
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGBoosterPredict
  * Signature: (JJII[[F)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterPredict
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGBoosterPredict
   (JNIEnv *, jclass, jlong, jlong, jint, jint, jobjectArray);
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGBoosterLoadModel
  * Signature: (JLjava/lang/String;)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterLoadModel
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGBoosterLoadModel
   (JNIEnv *, jclass, jlong, jstring);
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGBoosterSaveModel
  * Signature: (JLjava/lang/String;)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterSaveModel
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGBoosterSaveModel
   (JNIEnv *, jclass, jlong, jstring);
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGBoosterLoadModelFromBuffer
  * Signature: (J[B)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterLoadModelFromBuffer
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGBoosterLoadModelFromBuffer
   (JNIEnv *, jclass, jlong, jbyteArray);
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGBoosterGetModelRaw
  * Signature: (J[[B)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterGetModelRaw
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGBoosterGetModelRaw
   (JNIEnv *, jclass, jlong, jobjectArray);
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGBoosterDumpModel
  * Signature: (JLjava/lang/String;I[[Ljava/lang/String;)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterDumpModel
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGBoosterDumpModel
   (JNIEnv *, jclass, jlong, jstring, jint, jobjectArray);
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGBoosterGetAttr
  * Signature: (JLjava/lang/String;[Ljava/lang/String;)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterGetAttr
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGBoosterGetAttr
   (JNIEnv *, jclass, jlong, jstring, jobjectArray);
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGBoosterSetAttr
  * Signature: (JLjava/lang/String;Ljava/lang/String;)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterSetAttr
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGBoosterSetAttr
   (JNIEnv *, jclass, jlong, jstring, jstring);
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGBoosterLoadRabitCheckpoint
  * Signature: (J[I)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterLoadRabitCheckpoint
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGBoosterLoadRabitCheckpoint
   (JNIEnv *, jclass, jlong, jintArray);
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    XGBoosterSaveRabitCheckpoint
  * Signature: (J)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_XGBoosterSaveRabitCheckpoint
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_XGBoosterSaveRabitCheckpoint
   (JNIEnv *, jclass, jlong);
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    RabitInit
  * Signature: ([Ljava/lang/String;)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_RabitInit
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_RabitInit
   (JNIEnv *, jclass, jobjectArray);
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    RabitFinalize
  * Signature: ()I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_RabitFinalize
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_RabitFinalize
   (JNIEnv *, jclass);
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    RabitTrackerPrint
  * Signature: (Ljava/lang/String;)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_RabitTrackerPrint
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_RabitTrackerPrint
   (JNIEnv *, jclass, jstring);
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    RabitGetRank
  * Signature: ([I)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_RabitGetRank
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_RabitGetRank
   (JNIEnv *, jclass, jintArray);
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    RabitGetWorldSize
  * Signature: ([I)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_RabitGetWorldSize
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_RabitGetWorldSize
   (JNIEnv *, jclass, jintArray);
 
 /*
- * Class:     ml_dmlc_xgboost4j_XgboostJNI
+ * Class:     ml_dmlc_xgboost4j_java_XGBoostJNI
  * Method:    RabitVersionNumber
  * Signature: ([I)I
  */
-JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_XgboostJNI_RabitVersionNumber
+JNIEXPORT jint JNICALL Java_ml_dmlc_xgboost4j_java_XGBoostJNI_RabitVersionNumber
   (JNIEnv *, jclass, jintArray);
 
 #ifdef __cplusplus
diff --git a/jvm-packages/xgboost4j/src/test/scala/ml/dmlc/xgboost4j/scala/DMatrixSuite.scala b/jvm-packages/xgboost4j/src/test/scala/ml/dmlc/xgboost4j/scala/DMatrixSuite.scala
index cf7494c98..e6646b95b 100644
--- a/jvm-packages/xgboost4j/src/test/scala/ml/dmlc/xgboost4j/scala/DMatrixSuite.scala
+++ b/jvm-packages/xgboost4j/src/test/scala/ml/dmlc/xgboost4j/scala/DMatrixSuite.scala
@@ -21,6 +21,7 @@ import java.util.Arrays
 import scala.util.Random
 
 import org.scalatest.FunSuite
+import ml.dmlc.xgboost4j.java.{DMatrix => JDMatrix}
 
 class DMatrixSuite extends FunSuite {
   test("create DMatrix from File") {