From 89d9049b2b8d0e04e35056fec2a89567dca202d0 Mon Sep 17 00:00:00 2001
From: wangzhenfei <wangzf@yonyou.com>
Date: Wed, 19 Sep 2018 15:30:58 +0800
Subject: [PATCH] Prevent generation negative numbers to produce null pointer
 exception

---
 .../masterslave/RoundRobinMasterSlaveLoadBalanceAlgorithm.java  | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sharding-core/src/main/java/io/shardingsphere/core/api/algorithm/masterslave/RoundRobinMasterSlaveLoadBalanceAlgorithm.java b/sharding-core/src/main/java/io/shardingsphere/core/api/algorithm/masterslave/RoundRobinMasterSlaveLoadBalanceAlgorithm.java
index 955c8c71b0316..fe7effb48b009 100644
--- a/sharding-core/src/main/java/io/shardingsphere/core/api/algorithm/masterslave/RoundRobinMasterSlaveLoadBalanceAlgorithm.java
+++ b/sharding-core/src/main/java/io/shardingsphere/core/api/algorithm/masterslave/RoundRobinMasterSlaveLoadBalanceAlgorithm.java
@@ -35,6 +35,6 @@ public String getDataSource(final String name, final String masterDataSourceName
         AtomicInteger count = COUNT_MAP.containsKey(name) ? COUNT_MAP.get(name) : new AtomicInteger(0);
         COUNT_MAP.putIfAbsent(name, count);
         count.compareAndSet(slaveDataSourceNames.size(), 0);
-        return slaveDataSourceNames.get(count.getAndIncrement() % slaveDataSourceNames.size());
+        return slaveDataSourceNames.get(Math.abs(count.getAndIncrement()) % slaveDataSourceNames.size());
     }
 }