diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/types/Metadata.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/types/Metadata.scala
index 4979aced145c9..b6a859b75c37f 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/types/Metadata.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/types/Metadata.scala
@@ -190,6 +190,8 @@ object Metadata {
         JBool(x)
       case x: String =>
         JString(x)
+      case null =>
+        JNull
       case x: Metadata =>
         toJsonValue(x.map)
       case other =>
diff --git a/sql/catalyst/src/test/scala/org/apache/spark/sql/types/MetadataSuite.scala b/sql/catalyst/src/test/scala/org/apache/spark/sql/types/MetadataSuite.scala
index 210e65708170f..b4aeac562d2b8 100644
--- a/sql/catalyst/src/test/scala/org/apache/spark/sql/types/MetadataSuite.scala
+++ b/sql/catalyst/src/test/scala/org/apache/spark/sql/types/MetadataSuite.scala
@@ -26,6 +26,7 @@ class MetadataSuite extends SparkFunSuite {
     assert(meta.## !== 0)
     assert(meta.getString("key") === "value")
     assert(meta.contains("key"))
+    assert(meta === Metadata.fromJson(meta.json))
     intercept[NoSuchElementException](meta.getString("no_such_key"))
     intercept[ClassCastException](meta.getBoolean("key"))
   }
@@ -36,6 +37,7 @@ class MetadataSuite extends SparkFunSuite {
     assert(meta.## !== 0)
     assert(meta.getLong("key") === 12)
     assert(meta.contains("key"))
+    assert(meta === Metadata.fromJson(meta.json))
     intercept[NoSuchElementException](meta.getLong("no_such_key"))
     intercept[ClassCastException](meta.getBoolean("key"))
   }
@@ -46,6 +48,7 @@ class MetadataSuite extends SparkFunSuite {
     assert(meta.## !== 0)
     assert(meta.getDouble("key") === 12)
     assert(meta.contains("key"))
+    assert(meta === Metadata.fromJson(meta.json))
     intercept[NoSuchElementException](meta.getDouble("no_such_key"))
     intercept[ClassCastException](meta.getBoolean("key"))
   }
@@ -56,6 +59,7 @@ class MetadataSuite extends SparkFunSuite {
     assert(meta.## !== 0)
     assert(meta.getBoolean("key") === true)
     assert(meta.contains("key"))
+    assert(meta === Metadata.fromJson(meta.json))
     intercept[NoSuchElementException](meta.getBoolean("no_such_key"))
     intercept[ClassCastException](meta.getString("key"))
   }
@@ -69,6 +73,7 @@ class MetadataSuite extends SparkFunSuite {
     assert(meta.getLong("key") === 0)
     assert(meta.getBoolean("key") === false)
     assert(meta.contains("key"))
+    assert(meta === Metadata.fromJson(meta.json))
     intercept[NoSuchElementException](meta.getLong("no_such_key"))
   }
 }