Fixing JMX re-registration issue

Author: barancev

java/server/src/org/openqa/selenium/remote/server/jmx/JMXHelper.java

@@ -19,17 +19,20 @@
 
 import java.lang.management.ManagementFactory;
 
+import javax.management.InstanceAlreadyExistsException;
 import javax.management.MBeanServer;
 import javax.management.ObjectName;
 
 public class JMXHelper {
 
   public MBean register(Object bean) {
     MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();
+    MBean mBean = new MBean(bean);
     try {
-      MBean mBean = new MBean(bean);
       mbs.registerMBean(mBean, mBean.getObjectName());
       return mBean;
+    } catch (InstanceAlreadyExistsException t) {
+      return mBean;
     } catch (Throwable t) {
       t.printStackTrace();
       return null;