I have got a SPRING application. When I run
mvn jetty:run
everything is ok.
I would like to use JMX
Caused by: javax.management.InstanceAlreadyExistsException: bean:name=testBean1
This is trying to tell you that you have 2 beans with the same name ObjectName of bean:name=testBean1 being register with the MBeanExporter. However, unless there are other XML files or more entries in your beans map then there should not be.
I have no even idea how to debug it.
You could put a breakpoint in the JmxMBeanServer.registerMBean(...) method to see what beans are being registered to see if you can figure out why you are getting a duplicate.
As an aside, my SimpleJMX library is an easy way to export your beans via JMX. There is pretty good Spring support as well. Here are the documentation about using with Spring. There is also a Spring test program which demonstrates what you need to do to get it working. Here's the Spring XML file.