[SPARK-32999][SQL] Use Utils.getSimpleName to avoid hitting Malformed…

… class name in TreeNode

### What changes were proposed in this pull request?

Use `Utils.getSimpleName` to avoid hitting `Malformed class name` error in `TreeNode`.

### Why are the changes needed?

On older JDK versions (e.g. JDK8u), nested Scala classes may trigger `java.lang.Class.getSimpleName` to throw an `java.lang.InternalError: Malformed class name` error.

Similar to #29050, we should use  Spark's `Utils.getSimpleName` utility function in place of `Class.getSimpleName` to avoid hitting the issue.

### Does this PR introduce _any_ user-facing change?

Fixes a bug that throws an error when invoking `TreeNode.nodeName`, otherwise no changes.

### How was this patch tested?

Added new unit test case in `TreeNodeSuite`. Note that the test case assumes the test code can trigger the expected error, otherwise it'll skip the test safely, for compatibility with newer JDKs.

Manually tested on JDK8u and JDK11u and observed expected behavior:
- JDK8u: the test case triggers the "Malformed class name" issue and the fix works;
- JDK11u: the test case does not trigger the "Malformed class name" issue, and the test case is safely skipped.

Closes #29875 from rednaxelafx/spark-32999-getsimplename.

Authored-by: Kris Mok <kris.mok@databricks.com>
Signed-off-by: Dongjoon Hyun <dhyun@apple.com>

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/trees/TreeNode.scala

@@ -41,6 +41,7 @@ import org.apache.spark.sql.internal.SQLConf
 import org.apache.spark.sql.types._
 import org.apache.spark.sql.util.CaseInsensitiveStringMap
 import org.apache.spark.storage.StorageLevel
+import org.apache.spark.util.Utils
 
 /** Used by [[TreeNode.getNodeNumbered]] when traversing the tree for a given number */
 private class MutableInt(var i: Int)
@@ -521,11 +522,13 @@ abstract class TreeNode[BaseType <: TreeNode[BaseType]] extends Product {
     mapChildren(_.clone(), forceCopy = true)
   }
 
+  private def simpleClassName: String = Utils.getSimpleName(this.getClass)
+
   /**
    * Returns the name of this type of TreeNode.  Defaults to the class name.
    * Note that we remove the "Exec" suffix for physical operators here.
    */
-  def nodeName: String = getClass.getSimpleName.replaceAll("Exec$", "")
+  def nodeName: String = simpleClassName.replaceAll("Exec$", "")
 
   /**
    * The arguments that should be included in the arg string.  Defaults to the `productIterator`.
@@ -747,7 +750,7 @@ abstract class TreeNode[BaseType <: TreeNode[BaseType]] extends Product {
   protected def jsonFields: List[JField] = {
     val fieldNames = getConstructorParameterNames(getClass)
     val fieldValues = productIterator.toSeq ++ otherCopyArgs
-    assert(fieldNames.length == fieldValues.length, s"${getClass.getSimpleName} fields: " +
+    assert(fieldNames.length == fieldValues.length, s"$simpleClassName fields: " +
       fieldNames.mkString(", ") + s", values: " + fieldValues.mkString(", "))
 
     fieldNames.zip(fieldValues).map {
@@ -801,7 +804,7 @@ abstract class TreeNode[BaseType <: TreeNode[BaseType]] extends Product {
       try {
         val fieldNames = getConstructorParameterNames(p.getClass)
         val fieldValues = p.productIterator.toSeq
-        assert(fieldNames.length == fieldValues.length, s"${getClass.getSimpleName} fields: " +
+        assert(fieldNames.length == fieldValues.length, s"$simpleClassName fields: " +
           fieldNames.mkString(", ") + s", values: " + fieldValues.mkString(", "))
         ("product-class" -> JString(p.getClass.getName)) :: fieldNames.zip(fieldValues).map {
           case (name, value) => name -> parseToJson(value)

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/trees/TreeNodeSuite.scala

@@ -736,4 +736,30 @@ class TreeNodeSuite extends SparkFunSuite with SQLHelper {
     assertDifferentInstance(leaf, leafCloned)
     assert(leaf.child.eq(leafCloned.asInstanceOf[FakeLeafPlan].child))
   }
+
+  object MalformedClassObject extends Serializable {
+    case class MalformedNameExpression(child: Expression) extends TaggingExpression
+  }
+
+  test("SPARK-32999: TreeNode.nodeName should not throw malformed class name error") {
+    val testTriggersExpectedError = try {
+      classOf[MalformedClassObject.MalformedNameExpression].getSimpleName
+      false
+    } catch {
+      case ex: java.lang.InternalError if ex.getMessage.contains("Malformed class name") =>
+        true
+      case ex: Throwable => throw ex
+    }
+    // This test case only applies on older JDK versions (e.g. JDK8u), and doesn't trigger the
+    // issue on newer JDK versions (e.g. JDK11u).
+    assume(testTriggersExpectedError, "the test case didn't trigger malformed class name error")
+
+    val expr = MalformedClassObject.MalformedNameExpression(Literal(1))
+    try {
+      expr.nodeName
+    } catch {
+      case ex: java.lang.InternalError if ex.getMessage.contains("Malformed class name") =>
+        fail("TreeNode.nodeName should not throw malformed class name error")
+    }
+  }
 }