[SPARK-22330][CORE] Linear containsKey operation for serialized maps

…alization.

## What changes were proposed in this pull request?

Use non-linear containsKey operation for serialized maps, lookup into underlying map.

## How was this patch tested?

unit tests

Author: Alexander Istomin <istomin@rutarget.ru>

Closes #19553 from Whoosh/SPARK-22330.

core/src/main/scala/org/apache/spark/api/java/JavaUtils.scala

@@ -43,10 +43,17 @@ private[spark] object JavaUtils {
 
     override def size: Int = underlying.size
 
+    // Delegate to implementation because AbstractMap implementation iterates over whole key set
+    override def containsKey(key: AnyRef): Boolean = try {
+      underlying.contains(key.asInstanceOf[A])
+    } catch {
+      case _: ClassCastException => false
+    }
+
     override def get(key: AnyRef): B = try {
       underlying.getOrElse(key.asInstanceOf[A], null.asInstanceOf[B])
     } catch {
-      case ex: ClassCastException => null.asInstanceOf[B]
+      case _: ClassCastException => null.asInstanceOf[B]
     }
 
     override def entrySet: ju.Set[ju.Map.Entry[A, B]] = new ju.AbstractSet[ju.Map.Entry[A, B]] {

core/src/test/scala/org/apache/spark/api/java/JavaUtilsSuite.scala

@@ -0,0 +1,49 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.spark.api.java
+
+import java.io.Serializable
+
+import org.mockito.Mockito._
+
+import org.apache.spark.SparkFunSuite
+
+
+class JavaUtilsSuite extends SparkFunSuite {
+
+  test("containsKey implementation without iteratively entrySet call") {
+    val src = new scala.collection.mutable.HashMap[Double, String]
+    val key: Double = 42.5
+    val key2 = "key"
+
+    src.put(key, "42")
+
+    val map: java.util.Map[Double, String] = spy(JavaUtils.mapAsSerializableJavaMap(src))
+
+    assert(map.containsKey(key))
+
+    // ClassCast checking, shouldn't throw exception
+    assert(!map.containsKey(key2))
+    assert(map.get(key2) == null)
+
+    assert(map.get(key).eq("42"))
+    assert(map.isInstanceOf[Serializable])
+
+    verify(map, never()).entrySet()
+  }
+}