From 1934d408c15c76ba016dc527f941d21c30eabb8a Mon Sep 17 00:00:00 2001
From: Artem Bilan <abilan@pivotal.io>
Date: Wed, 7 Oct 2015 10:29:50 -0400
Subject: [PATCH] INT-3843: Backport  NPE Fix for TCP ConFactories

JIRA: https://jira.spring.io/browse/INT-3843

**Cherry-pick to the 3.0.x**

Conflicts:
	spring-integration-ip/src/main/java/org/springframework/integration/ip/tcp/connection/TcpNioServerConnectionFactory.java
Resolved.
---
 .../TcpNetServerConnectionFactory.java           | 10 +++++++++-
 .../TcpNioServerConnectionFactory.java           | 16 +++++++++++-----
 2 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/spring-integration-ip/src/main/java/org/springframework/integration/ip/tcp/connection/TcpNetServerConnectionFactory.java b/spring-integration-ip/src/main/java/org/springframework/integration/ip/tcp/connection/TcpNetServerConnectionFactory.java
index 0504f2f693..17da270f05 100644
--- a/spring-integration-ip/src/main/java/org/springframework/integration/ip/tcp/connection/TcpNetServerConnectionFactory.java
+++ b/spring-integration-ip/src/main/java/org/springframework/integration/ip/tcp/connection/TcpNetServerConnectionFactory.java
@@ -80,7 +80,15 @@ public class TcpNetServerConnectionFactory extends AbstractServerConnectionFacto
 				 *  Not fatal.
 				 */
 				try {
-					socket = serverSocket.accept();
+					if (this.serverSocket == null) {
+						if (logger.isDebugEnabled()) {
+							logger.debug(this + " stopped before accept");
+						}
+						throw new IOException(this + " stopped before accept");
+					}
+					else {
+						socket = this.serverSocket.accept();
+					}
 				}
 				catch (SocketTimeoutException ste) {
 					if (logger.isDebugEnabled()) {
diff --git a/spring-integration-ip/src/main/java/org/springframework/integration/ip/tcp/connection/TcpNioServerConnectionFactory.java b/spring-integration-ip/src/main/java/org/springframework/integration/ip/tcp/connection/TcpNioServerConnectionFactory.java
index 782df53890..6ddf419c20 100644
--- a/spring-integration-ip/src/main/java/org/springframework/integration/ip/tcp/connection/TcpNioServerConnectionFactory.java
+++ b/spring-integration-ip/src/main/java/org/springframework/integration/ip/tcp/connection/TcpNioServerConnectionFactory.java
@@ -92,11 +92,17 @@ public class TcpNioServerConnectionFactory extends AbstractServerConnectionFacto
 						Math.abs(this.getBacklog()));
 			}
 			final Selector selector = Selector.open();
-			this.serverChannel.register(selector, SelectionKey.OP_ACCEPT);
-			this.setListening(true);
-			this.selector = selector;
-			doSelect(this.serverChannel, selector);
-
+			if (this.serverChannel == null) {
+				if (logger.isDebugEnabled()) {
+					logger.debug(this + " stopped before registering the server channel");
+				}
+			}
+			else {
+				this.serverChannel.register(selector, SelectionKey.OP_ACCEPT);
+				setListening(true);
+				this.selector = selector;
+				doSelect(this.serverChannel, selector);
+			}
 		}
 		catch (IOException e) {
 			this.close();