diff --git a/wayang-api/wayang-api-scala-java/src/main/scala/org/apache/wayang/api/DataQuanta.scala b/wayang-api/wayang-api-scala-java/src/main/scala/org/apache/wayang/api/DataQuanta.scala
index ab41cba6d..ac16fcc21 100644
--- a/wayang-api/wayang-api-scala-java/src/main/scala/org/apache/wayang/api/DataQuanta.scala
+++ b/wayang-api/wayang-api-scala-java/src/main/scala/org/apache/wayang/api/DataQuanta.scala
@@ -942,7 +942,7 @@ class DataQuanta[Out: ClassTag](val operator: ElementaryOperator, outputIndex: I
     collector
   }
 
-  def explain(): Unit = {
+  def explain(toJson: Boolean = false): Unit = {
     // Set up the sink.
     val collector = new java.util.LinkedList[Out]()
     val sink = LocalCallbackSink.createCollectingSink(collector, dataSetType[Out])
@@ -951,7 +951,7 @@ class DataQuanta[Out: ClassTag](val operator: ElementaryOperator, outputIndex: I
 
     // Do the explanation.
     this.planBuilder.sinks += sink
-    this.planBuilder.buildAndExplain()
+    this.planBuilder.buildAndExplain(toJson)
   }
 
 
diff --git a/wayang-api/wayang-api-scala-java/src/main/scala/org/apache/wayang/api/PlanBuilder.scala b/wayang-api/wayang-api-scala-java/src/main/scala/org/apache/wayang/api/PlanBuilder.scala
index 2def92da8..f6df3e344 100644
--- a/wayang-api/wayang-api-scala-java/src/main/scala/org/apache/wayang/api/PlanBuilder.scala
+++ b/wayang-api/wayang-api-scala-java/src/main/scala/org/apache/wayang/api/PlanBuilder.scala
@@ -109,9 +109,13 @@ class PlanBuilder(private[api] val wayangContext: WayangContext, private var job
   /**
     * Build the [[org.apache.wayang.core.api.Job]] and explain it.
     */
-  def buildAndExplain(): Unit = {
+  def buildAndExplain(toJson: Boolean = false): Unit = {
     val plan: WayangPlan = new WayangPlan(this.sinks.toArray: _*)
-    this.wayangContext.explain(plan, this.udfJars.toArray: _*)
+    if (toJson) {
+      this.wayangContext.explain(plan, toJson, this.udfJars.toArray: _*)
+    } else {
+      this.wayangContext.explain(plan, this.udfJars.toArray: _*)
+    }
   }
 
   /**