From 09b979c5af374a548b9ccbc4a6f08801bbce38bf Mon Sep 17 00:00:00 2001
From: wu-sheng <wu.sheng@foxmail.com>
Date: Tue, 19 Dec 2017 15:27:14 +0800
Subject: [PATCH] Fix npe

---
 .../skywalking/apm/agent/core/sampling/SamplingService.java | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/sampling/SamplingService.java b/apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/sampling/SamplingService.java
index 15d831427..e2910bba6 100644
--- a/apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/sampling/SamplingService.java
+++ b/apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/sampling/SamplingService.java
@@ -26,10 +26,10 @@ import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicInteger;
 import org.apache.skywalking.apm.agent.core.boot.BootService;
 import org.apache.skywalking.apm.agent.core.boot.DefaultNamedThreadFactory;
+import org.apache.skywalking.apm.agent.core.conf.Config;
 import org.apache.skywalking.apm.agent.core.context.trace.TraceSegment;
 import org.apache.skywalking.apm.agent.core.logging.api.ILog;
 import org.apache.skywalking.apm.agent.core.logging.api.LogManager;
-import org.apache.skywalking.apm.agent.core.conf.Config;
 
 /**
  * The <code>SamplingService</code> take charge of how to sample the {@link TraceSegment}. Every {@link TraceSegment}s
@@ -83,7 +83,9 @@ public class SamplingService implements BootService {
 
     @Override
     public void shutdown() throws Throwable {
-        scheduledFuture.cancel(true);
+        if (scheduledFuture != null) {
+            scheduledFuture.cancel(true);
+        }
     }
 
     /**