diff --git a/src/main/scala/com/microsoft/ml/spark/lightgbm/LightGBMBooster.scala b/src/main/scala/com/microsoft/ml/spark/lightgbm/LightGBMBooster.scala
index e930cb1bec..7f626bcf63 100644
--- a/src/main/scala/com/microsoft/ml/spark/lightgbm/LightGBMBooster.scala
+++ b/src/main/scala/com/microsoft/ml/spark/lightgbm/LightGBMBooster.scala
@@ -8,16 +8,18 @@ import com.microsoft.ml.spark.lightgbm.LightGBMUtils.getBoosterPtrFromModelStrin
 import org.apache.spark.ml.linalg.{DenseVector, SparseVector, Vector}
 import org.apache.spark.sql.{SaveMode, SparkSession}
 
-class BoosterHandler(model: String) extends Serializable {
+protected class BoosterHandler(model: String) extends Serializable {
 
   LightGBMUtils.initializeNativeLibrary()
 
+  @transient
   lazy val boosterPtr: SWIGTYPE_p_void = {
     getBoosterPtrFromModelString(model)
   }
 
   lazy val rawScoreConstant = lightgbmlibConstants.C_API_PREDICT_RAW_SCORE
   lazy val normalScoreConstant = lightgbmlibConstants.C_API_PREDICT_RAW_SCORE
+  lazy val leafIndexPredictConstant = lightgbmlibConstants.C_API_PREDICT_LEAF_INDEX
 
   lazy val dataInt32bitType = lightgbmlibConstants.C_API_DTYPE_INT32
   lazy val data64bitType = lightgbmlibConstants.C_API_DTYPE_FLOAT64
@@ -113,7 +115,7 @@ class LightGBMBooster(val model: String) extends Serializable {
   }
 
   protected def predictScoreForMat(row: Array[Double], kind: Int, classification: Boolean): Array[Double] = {
-    val data64bitType = lightgbmlibConstants.C_API_DTYPE_FLOAT64
+    val data64bitType = boosterHandler.data64bitType
 
     val numCols = row.length
     val isRowMajor = 1
@@ -134,15 +136,15 @@ class LightGBMBooster(val model: String) extends Serializable {
     val numCols = sparseVector.size
 
     val datasetParams = "max_bin=255 is_pre_partition=True"
-    val dataInt32bitType = lightgbmlibConstants.C_API_DTYPE_INT32
-    val data64bitType = lightgbmlibConstants.C_API_DTYPE_FLOAT64
+    val dataInt32bitType = boosterHandler.dataInt32bitType
+    val data64bitType = boosterHandler.data64bitType
 
     LightGBMUtils.validate(
       lightgbmlib.LGBM_BoosterPredictForCSRSingle(
         sparseVector.indices, sparseVector.values,
         sparseVector.numNonzeros,
         boosterHandler.boosterPtr, dataInt32bitType, data64bitType, 2, numCols,
-        lightgbmlibConstants.C_API_PREDICT_LEAF_INDEX, -1, datasetParams,
+        boosterHandler.leafIndexPredictConstant, -1, datasetParams,
         leafIndexDataLengthLongPtr, leafIndexDataOutPtr), "Booster Predict Leaf")
 
     predLeafToArray(leafIndexDataOutPtr)
@@ -160,7 +162,7 @@ class LightGBMBooster(val model: String) extends Serializable {
       lightgbmlib.LGBM_BoosterPredictForMatSingle(
         row, boosterHandler.boosterPtr, data64bitType,
         numCols,
-        isRowMajor, lightgbmlibConstants.C_API_PREDICT_LEAF_INDEX,
+        isRowMajor, boosterHandler.leafIndexPredictConstant,
         -1, datasetParams, leafIndexDataLengthLongPtr, leafIndexDataOutPtr),
       "Booster Predict Leaf")