A single call to JavaTypeUtils.getTypeArguments is required to get ty…

…pe variables from the class inheritance hierarchy

sql/api/src/main/scala/org/apache/spark/sql/catalyst/JavaTypeInference.scala

@@ -21,7 +21,6 @@ import java.lang.reflect.{ParameterizedType, Type, TypeVariable}
 import java.util.{List => JList, Map => JMap}
 import javax.annotation.Nonnull
 
-import scala.annotation.tailrec
 import scala.collection.JavaConverters._
 import scala.reflect.ClassTag
 
@@ -131,7 +130,9 @@ object JavaTypeInference {
       // TODO: we should only collect properties that have getter and setter. However, some tests
       //   pass in scala case class as java bean class which doesn't have getter and setter.
       val properties = getJavaBeanReadableProperties(c)
-      val classTV = getClassHierarchyTypeArguments(c, typeVariables)
+      // add type variables from inheritance hierarchy of the class
+      val classTV = JavaTypeUtils.getTypeArguments(c, classOf[Object]).asScala.toMap ++
+        typeVariables
       // Note that the fields are ordered by name.
       val fields = properties.map { property =>
         val readMethod = property.getReadMethod
@@ -158,17 +159,4 @@ object JavaTypeInference {
       .filterNot(_.getName == "declaringClass")
       .filter(_.getReadMethod != null)
   }
-
-  @tailrec
-  def getClassHierarchyTypeArguments(cls: Class[_],
-                                     typeVariables: Map[TypeVariable[_], Type])
-  : Map[TypeVariable[_], Type] = {
-    if (cls == null) {
-      return typeVariables;
-    }
-
-    getClassHierarchyTypeArguments(cls.getSuperclass, typeVariables ++
-      JavaTypeUtils.getTypeArguments(cls, classOf[Object]).asScala.toMap
-    )
-  }
 }