JMS SingleConnectionFactory uses minimized number of start calls (for Oracle AQ; SPR-5987)

org.springframework.jms/src/main/java/org/springframework/jms/connection/SingleConnectionFactory.java

@@ -510,8 +510,10 @@ public class SingleConnectionFactory
 			else if (method.getName().equals("start")) {
 				// Handle start method: track started state.
 				synchronized (connectionMonitor) {
-					this.target.start();
-					started = true;
+					if (!started) {
+						this.target.start();
+						started = true;
+					}
 				}
 				return null;
 			}