Avoid use of JDBC4-only isClosed()

Author: srowen

core/src/main/scala/org/apache/spark/rdd/JdbcRDD.scala

@@ -99,21 +99,21 @@ class JdbcRDD[T: ClassTag](
 
     override def close() {
       try {
-        if (null != rs && ! rs.isClosed()) {
+        if (null != rs) {
           rs.close()
         }
       } catch {
         case e: Exception => logWarning("Exception closing resultset", e)
       }
       try {
-        if (null != stmt && ! stmt.isClosed()) {
+        if (null != stmt) {
           stmt.close()
         }
       } catch {
         case e: Exception => logWarning("Exception closing statement", e)
       }
       try {
-        if (null != conn && ! conn.isClosed()) {
+        if (null != conn) {
           conn.close()
         }
         logInfo("closed connection")

sql/core/src/main/scala/org/apache/spark/sql/jdbc/JDBCRDD.scala

@@ -369,21 +369,21 @@ private[sql] class JDBCRDD(
     def close() {
       if (closed) return
       try {
-        if (null != rs && ! rs.isClosed()) {
+        if (null != rs) {
           rs.close()
         }
       } catch {
         case e: Exception => logWarning("Exception closing resultset", e)
       }
       try {
-        if (null != stmt && ! stmt.isClosed()) {
+        if (null != stmt) {
           stmt.close()
         }
       } catch {
         case e: Exception => logWarning("Exception closing statement", e)
       }
       try {
-        if (null != conn && ! conn.isClosed()) {
+        if (null != conn) {
           conn.close()
         }
         logInfo("closed connection")