[FIXED JENKINS-15226] Log recorders do not work reliably.

changelog.html

@@ -55,6 +55,9 @@ Upcoming changes</a>
 <!-- Record your changes in the trunk here. -->
 <div id="trunk" style="display:none"><!--=TRUNK-BEGIN=-->
 <ul class=image>
+  <li class=bug>
+    Log recorders do not work reliably.
+    (<a href="https://issues.jenkins-ci.org/browse/JENKINS-15226">issue 15226</a>)
   <li class=>
 </ul>
 </div><!--=TRUNK-END=-->

core/src/main/java/hudson/logging/LogRecorder.java

@@ -87,6 +87,7 @@ public class LogRecorder extends AbstractModelObject implements Saveable {
     public static final class Target {
         public final String name;
         private final int level;
+        private transient /* almost final*/ Logger logger;
 
         public Target(String name, Level level) {
             this(name,level.intValue());
@@ -118,7 +119,10 @@ public class LogRecorder extends AbstractModelObject implements Saveable {
         }
 
         public Logger getLogger() {
-            return Logger.getLogger(name);
+            if (logger == null) {
+                logger = Logger.getLogger(name);
+            }
+            return logger;
         }
 
         /**