diff --git a/sql/core/src/main/scala/org/apache/spark/sql/json/JsonRDD.scala b/sql/core/src/main/scala/org/apache/spark/sql/json/JsonRDD.scala
index 61ee960aad..bf32da1b71 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/json/JsonRDD.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/json/JsonRDD.scala
@@ -242,14 +242,14 @@ private[sql] object JsonRDD extends Logging {
         def buildKeyPathForInnerStructs(v: Any, t: DataType): Seq[(String, DataType)] = t match {
           case ArrayType(StructType(Nil), containsNull) => {
             // The elements of this arrays are structs.
-            v.asInstanceOf[Seq[Map[String, Any]]].flatMap {
+            v.asInstanceOf[Seq[Map[String, Any]]].flatMap(Option(_)).flatMap {
               element => allKeysWithValueTypes(element)
             }.map {
               case (k, t) => (s"$key.$k", t)
             }
           }
           case ArrayType(t1, containsNull) =>
-            v.asInstanceOf[Seq[Any]].flatMap {
+            v.asInstanceOf[Seq[Any]].flatMap(Option(_)).flatMap {
               element => buildKeyPathForInnerStructs(element, t1)
             }
           case other => Nil
diff --git a/sql/core/src/test/scala/org/apache/spark/sql/json/JsonSuite.scala b/sql/core/src/test/scala/org/apache/spark/sql/json/JsonSuite.scala
index 7bb08f1b51..41927e8369 100644
--- a/sql/core/src/test/scala/org/apache/spark/sql/json/JsonSuite.scala
+++ b/sql/core/src/test/scala/org/apache/spark/sql/json/JsonSuite.scala
@@ -208,7 +208,7 @@ class JsonSuite extends QueryTest {
   }
 
   test("Complex field and type inferring") {
-    val jsonSchemaRDD = jsonRDD(complexFieldAndType)
+    val jsonSchemaRDD = jsonRDD(complexFieldAndType1)
 
     val expectedSchema = StructType(
       StructField("arrayOfArray1", ArrayType(ArrayType(StringType, false), false), true) ::
@@ -305,7 +305,7 @@ class JsonSuite extends QueryTest {
   }
 
   ignore("Complex field and type inferring (Ignored)") {
-    val jsonSchemaRDD = jsonRDD(complexFieldAndType)
+    val jsonSchemaRDD = jsonRDD(complexFieldAndType1)
     jsonSchemaRDD.registerTempTable("jsonTable")
 
     // Right now, "field1" and "field2" are treated as aliases. We should fix it.
@@ -707,4 +707,35 @@ class JsonSuite extends QueryTest {
 
     TestSQLContext.setConf(SQLConf.COLUMN_NAME_OF_CORRUPT_RECORD, oldColumnNameOfCorruptRecord)
   }
+
+  test("SPARK-4068: nulls in arrays") {
+    val jsonSchemaRDD = jsonRDD(nullsInArrays)
+    jsonSchemaRDD.registerTempTable("jsonTable")
+
+    val schema = StructType(
+      StructField("field1",
+        ArrayType(ArrayType(ArrayType(ArrayType(StringType, false), false), true), false), true) ::
+      StructField("field2",
+        ArrayType(ArrayType(
+          StructType(StructField("Test", IntegerType, true) :: Nil), false), true), true) ::
+      StructField("field3",
+        ArrayType(ArrayType(
+          StructType(StructField("Test", StringType, true) :: Nil), true), false), true) ::
+      StructField("field4",
+        ArrayType(ArrayType(ArrayType(IntegerType, false), true), false), true) :: Nil)
+
+    assert(schema === jsonSchemaRDD.schema)
+
+    checkAnswer(
+      sql(
+        """
+          |SELECT field1, field2, field3, field4
+          |FROM jsonTable
+        """.stripMargin),
+      Seq(Seq(Seq(null), Seq(Seq(Seq("Test")))), null, null, null) ::
+      Seq(null, Seq(null, Seq(Seq(1))), null, null) ::
+      Seq(null, null, Seq(Seq(null), Seq(Seq("2"))), null) ::
+      Seq(null, null, null, Seq(Seq(null, Seq(1, 2, 3)))) :: Nil
+    )
+  }
 }
diff --git a/sql/core/src/test/scala/org/apache/spark/sql/json/TestJsonData.scala b/sql/core/src/test/scala/org/apache/spark/sql/json/TestJsonData.scala
index eaca9f0508..c204162dd2 100644
--- a/sql/core/src/test/scala/org/apache/spark/sql/json/TestJsonData.scala
+++ b/sql/core/src/test/scala/org/apache/spark/sql/json/TestJsonData.scala
@@ -32,22 +32,6 @@ object TestJsonData {
           "null":null
       }"""  :: Nil)
 
-  val complexFieldAndType =
-    TestSQLContext.sparkContext.parallelize(
-      """{"struct":{"field1": true, "field2": 92233720368547758070},
-          "structWithArrayFields":{"field1":[4, 5, 6], "field2":["str1", "str2"]},
-          "arrayOfString":["str1", "str2"],
-          "arrayOfInteger":[1, 2147483647, -2147483648],
-          "arrayOfLong":[21474836470, 9223372036854775807, -9223372036854775808],
-          "arrayOfBigInteger":[922337203685477580700, -922337203685477580800],
-          "arrayOfDouble":[1.2, 1.7976931348623157E308, 4.9E-324, 2.2250738585072014E-308],
-          "arrayOfBoolean":[true, false, true],
-          "arrayOfNull":[null, null, null, null],
-          "arrayOfStruct":[{"field1": true, "field2": "str1"}, {"field1": false}, {"field3": null}],
-          "arrayOfArray1":[[1, 2, 3], ["str1", "str2"]],
-          "arrayOfArray2":[[1, 2, 3], [1.1, 2.1, 3.1]]
-         }"""  :: Nil)
-
   val primitiveFieldValueTypeConflict =
     TestSQLContext.sparkContext.parallelize(
       """{"num_num_1":11, "num_num_2":null, "num_num_3": 1.1,
@@ -83,6 +67,22 @@ object TestJsonData {
       """{"d":{"field":true}}""" ::
       """{"e":"str"}""" :: Nil)
 
+  val complexFieldAndType1 =
+    TestSQLContext.sparkContext.parallelize(
+      """{"struct":{"field1": true, "field2": 92233720368547758070},
+          "structWithArrayFields":{"field1":[4, 5, 6], "field2":["str1", "str2"]},
+          "arrayOfString":["str1", "str2"],
+          "arrayOfInteger":[1, 2147483647, -2147483648],
+          "arrayOfLong":[21474836470, 9223372036854775807, -9223372036854775808],
+          "arrayOfBigInteger":[922337203685477580700, -922337203685477580800],
+          "arrayOfDouble":[1.2, 1.7976931348623157E308, 4.9E-324, 2.2250738585072014E-308],
+          "arrayOfBoolean":[true, false, true],
+          "arrayOfNull":[null, null, null, null],
+          "arrayOfStruct":[{"field1": true, "field2": "str1"}, {"field1": false}, {"field3": null}],
+          "arrayOfArray1":[[1, 2, 3], ["str1", "str2"]],
+          "arrayOfArray2":[[1, 2, 3], [1.1, 2.1, 3.1]]
+         }"""  :: Nil)
+
   val complexFieldAndType2 =
     TestSQLContext.sparkContext.parallelize(
       """{"arrayOfStruct":[{"field1": true, "field2": "str1"}, {"field1": false}, {"field3": null}],
@@ -137,6 +137,13 @@ object TestJsonData {
           ]]
       }""" :: Nil)
 
+  val nullsInArrays =
+    TestSQLContext.sparkContext.parallelize(
+      """{"field1":[[null], [[["Test"]]]]}""" ::
+      """{"field2":[null, [{"Test":1}]]}""" ::
+      """{"field3":[[null], [{"Test":"2"}]]}""" ::
+      """{"field4":[[null, [1,2,3]]]}""" :: Nil)
+
   val jsonArray =
     TestSQLContext.sparkContext.parallelize(
       """[{"a":"str_a_1"}]""" ::