[kylin] 01/02: KYLIN-3584 Correct lazy initialization of DefaultScheduler.INSTANCE

[shaofengshi]

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shaofengshi pushed a commit to branch master
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commit 82cf3096e5cac09eb25c217629f4e440266d3b86
Author: chao long <wayn...@qq.com>
AuthorDate: Tue Sep 25 16:42:54 2018 +0800

    KYLIN-3584 Correct lazy initialization of DefaultScheduler.INSTANCE
---
 .../java/org/apache/kylin/job/impl/threadpool/DefaultScheduler.java | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git 
a/core-job/src/main/java/org/apache/kylin/job/impl/threadpool/DefaultScheduler.java
 
b/core-job/src/main/java/org/apache/kylin/job/impl/threadpool/DefaultScheduler.java
index c243757..df3f6fa 100644
--- 
a/core-job/src/main/java/org/apache/kylin/job/impl/threadpool/DefaultScheduler.java
+++ 
b/core-job/src/main/java/org/apache/kylin/job/impl/threadpool/DefaultScheduler.java
@@ -51,7 +51,11 @@ public class DefaultScheduler implements 
Scheduler<AbstractExecutable>, Connecti
 
     public static DefaultScheduler getInstance() {
         if (INSTANCE == null) {
-            INSTANCE = createInstance();
+            synchronized (DefaultScheduler.class) {
+                if (INSTANCE == null) {
+                    INSTANCE = createInstance();
+                }
+            }
         }
         return INSTANCE;
     }