[SPARK-22291][SQL] Conversion error when transforming array types of uuid, inet and cidr to StingType in PostgreSQL

external/docker-integration-tests/src/test/scala/org/apache/spark/sql/jdbc/PostgresIntegrationSuite.scala

@@ -55,6 +55,19 @@ class PostgresIntegrationSuite extends DockerJDBCIntegrationSuite {
       + "null, null, null, null, null, "
       + "null, null, null, null, null, null, null)"
     ).executeUpdate()
+
+    conn.prepareStatement("CREATE TABLE st_with_array (c0 uuid, c1 inet, c2 cidr," +
+      "c3 json, c4 jsonb, c5 uuid[], c6 inet[], c7 cidr[], c8 json[], c9 jsonb[])")
+      .executeUpdate()
+    conn.prepareStatement("INSERT INTO st_with_array VALUES ( " +
+      "'0a532531-cdf1-45e3-963d-5de90b6a30f1', '172.168.22.1', '192.168.100.128/25', " +
+      """'{"a": "foo", "b": "bar"}', '{"a": 1, "b": 2}', """ +
+      "ARRAY['7be8aaf8-650e-4dbb-8186-0a749840ecf2'," +
+      "'205f9bfc-018c-4452-a605-609c0cfad228']::uuid[], ARRAY['172.16.0.41', " +
+      "'172.16.0.42']::inet[], ARRAY['192.168.0.0/24', '10.1.0.0/16']::cidr[], " +
+      """ARRAY['{"a": "foo", "b": "bar"}', '{"a": 1, "b": 2}']::json[], """ +
+      """ARRAY['{"a": 1, "b": 2, "c": 3}']::jsonb[])"""
+    ).executeUpdate()
   }
 
   test("Type mapping for various types") {
@@ -126,4 +139,21 @@ class PostgresIntegrationSuite extends DockerJDBCIntegrationSuite {
     assert(schema(0).dataType == FloatType)
     assert(schema(1).dataType == ShortType)
   }
+
+  test("SPARK-22291: Conversion error when transforming array types of " +
+    "uuid, inet and cidr to StingType in PostgreSQL") {
+    val df = sqlContext.read.jdbc(jdbcUrl, "st_with_array", new Properties)
+    val rows = df.collect()
+    assert(rows(0).getString(0) == "0a532531-cdf1-45e3-963d-5de90b6a30f1")
+    assert(rows(0).getString(1) == "172.168.22.1")
+    assert(rows(0).getString(2) == "192.168.100.128/25")
+    assert(rows(0).getString(3) == "{\"a\": \"foo\", \"b\": \"bar\"}")
+    assert(rows(0).getString(4) == "{\"a\": 1, \"b\": 2}")
+    assert(rows(0).getSeq(5) == Seq("7be8aaf8-650e-4dbb-8186-0a749840ecf2",
+      "205f9bfc-018c-4452-a605-609c0cfad228"))
+    assert(rows(0).getSeq(6) == Seq("172.16.0.41", "172.16.0.42"))
+    assert(rows(0).getSeq(7) == Seq("192.168.0.0/24", "10.1.0.0/16"))
+    assert(rows(0).getSeq(8) == Seq("""{"a": "foo", "b": "bar"}""", """{"a": 1, "b": 2}"""))
+    assert(rows(0).getSeq(9) == Seq("""{"a": 1, "b": 2, "c": 3}"""))
+  }
 }

sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/jdbc/JdbcUtils.scala

@@ -440,8 +440,9 @@ object JdbcUtils extends Logging {
 
         case StringType =>
           (array: Object) =>
-            array.asInstanceOf[Array[java.lang.String]]
-              .map(UTF8String.fromString)
+            // some underling types are not String such as uuid, inet, cidr, etc.
+            array.asInstanceOf[Array[java.lang.Object]]
+              .map(obj => if (obj == null) null else UTF8String.fromString(obj.toString))
 
         case DateType =>
           (array: Object) =>