Update SQLConf.scala

use concurrent.ConcurrentHashMap instead of util.Collections.synchronizedMap

Author: baishuo(白硕) <vc_java@hotmail.com>

Closes #1272 from baishuo/master and squashes the following commits:

51ec55d [baishuo(白硕)] Update SQLConf.scala
63da043 [baishuo(白硕)] Update SQLConf.scala
36b6dbd [baishuo(白硕)] Update SQLConf.scala
864faa0 [baishuo(白硕)] Update SQLConf.scala
593096b [baishuo(白硕)] Update SQLConf.scala
7304d9b [baishuo(白硕)] Update SQLConf.scala
843581c [baishuo(白硕)] Update SQLConf.scala
1d3e4a2 [baishuo(白硕)] Update SQLConf.scala
0740f28 [baishuo(白硕)] Update SQLConf.scala

1 files changed, 3 insertions, 6 deletions

diff --git a/sql/core/src/main/scala/org/apache/spark/sql/SQLConf.scala b/sql/core/src/main/scala/org/apache/spark/sql/SQLConf.scala
index 3b5abab969..95ed0f2850 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/SQLConf.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/SQLConf.scala
@@ -64,20 +64,17 @@ trait SQLConf {
   }
 
   def get(key: String): String = {
-    if (!settings.containsKey(key)) {
-      throw new NoSuchElementException(key)
-    }
-    settings.get(key)
+    Option(settings.get(key)).getOrElse(throw new NoSuchElementException(key))
   }
 
   def get(key: String, defaultValue: String): String = {
-    if (!settings.containsKey(key)) defaultValue else settings.get(key)
+    Option(settings.get(key)).getOrElse(defaultValue)
   }
 
   def getAll: Array[(String, String)] = settings.asScala.toArray
 
   def getOption(key: String): Option[String] = {
-    if (!settings.containsKey(key)) None else Some(settings.get(key))
+    Option(settings.get(key))
   }
 
   def contains(key: String): Boolean = settings.containsKey(key)