Randomly, while starting a managed server, the following exception is logged in the log files. What does it mean, and how can I resolve this.

The WebLogic Server did not start up properly.
Exception raised:
java.lang.NullPointerException
at java.io.ObjectInputStream.inputClassFields(ObjectInputStream.java:2266)
at java.io.ObjectInputStream.defaultReadObject(ObjectInputStream.java:514)
at weblogic.management.internal.DynamicMBeanImpl.readObject(DynamicMBeanImpl.java:2167)
at java.lang.reflect.Method.invoke(Native Method)
at java.io.ObjectInputStream.invokeObjectReader(ObjectInputStream.java:2209)
at java.io.ObjectInputStream.inputObject(ObjectInputStream.java:1406)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:381)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:231)
at java.util.ArrayList.readObject(ArrayList.java:526)
at java.lang.reflect.Method.invoke(Native Method)
at java.io.ObjectInputStream.invokeObjectReader(ObjectInputStream.java:2209)
at java.io.ObjectInputStream.inputObject(ObjectInputStream.java:1406)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:381)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:231)
at weblogic.management.ManagedServerAdmin.bootstrapLocalServer(ManagedServerAdmin.java:214)
at weblogic.management.ManagedServerAdmin.initialize(ManagedServerAdmin.java:122)
at weblogic.t3.srvr.T3Srvr.initialize1(T3Srvr.java:659)
at weblogic.t3.srvr.T3Srvr.initialize(T3Srvr.java:589)
at weblogic.t3.srvr.T3Srvr.run(T3Srvr.java:277)
at weblogic.Server.main(Server.java:32)
--------------- nested within: ------------------
weblogic.management.configuration.ConfigurationException: Exception encountered connecting to http://machine1:7001/wl_management_internal2/
Bootstrap - with nested exception:
[java.lang.NullPointerException]
at weblogic.management.ManagedServerAdmin.bootstrapLocalServer(ManagedServerAdmin.java:235)
at weblogic.management.ManagedServerAdmin.initialize(ManagedServerAdmin.java:122)
at weblogic.t3.srvr.T3Srvr.initialize1(T3Srvr.java:659)
at weblogic.t3.srvr.T3Srvr.initialize(T3Srvr.java:589)
at weblogic.t3.srvr.T3Srvr.run(T3Srvr.java:277)
at weblogic.Server.main(Server.java:32)
Reason: Fatal initialization exception
Throwable: weblogic.management.configuration.ConfigurationException: Exception encountered connecting to http://machine1:7001/wl_management
_internal2/Bootstrap - with nested exception:
[java.lang.NullPointerException]
java.lang.NullPointerException
at java.io.ObjectInputStream.inputClassFields(ObjectInputStream.java:2266)
at java.io.ObjectInputStream.defaultReadObject(ObjectInputStream.java:514)
at weblogic.management.internal.DynamicMBeanImpl.readObject(DynamicMBeanImpl.java:2167)
at java.lang.reflect.Method.invoke(Native Method)
at java.io.ObjectInputStream.invokeObjectReader(ObjectInputStream.java:2209)
at java.io.ObjectInputStream.inputObject(ObjectInputStream.java:1406)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:381)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:231)
at java.util.ArrayList.readObject(ArrayList.java:526)
at java.lang.reflect.Method.invoke(Native Method)
at java.io.ObjectInputStream.invokeObjectReader(ObjectInputStream.java:2209)
at java.io.ObjectInputStream.inputObject(ObjectInputStream.java:1406)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:381)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:231)
at weblogic.management.ManagedServerAdmin.bootstrapLocalServer(ManagedServerAdmin.java:214)
at weblogic.management.ManagedServerAdmin.initialize(ManagedServerAdmin.java:122)
at weblogic.t3.srvr.T3Srvr.initialize1(T3Srvr.java:659)
at weblogic.t3.srvr.T3Srvr.initialize(T3Srvr.java:589)
at weblogic.t3.srvr.T3Srvr.run(T3Srvr.java:277)
at weblogic.Server.main(Server.java:32)
--------------- nested within: ------------------
weblogic.management.configuration.ConfigurationException: Exception encountered connecting to http://machine1:7001/wl_management_internal2/
Bootstrap - with nested exception:
[java.lang.NullPointerException]
at weblogic.management.ManagedServerAdmin.bootstrapLocalServer(ManagedServerAdmin.java:235)
at weblogic.management.ManagedServerAdmin.initialize(ManagedServerAdmin.java:122)
at weblogic.t3.srvr.T3Srvr.initialize1(T3Srvr.java:659)
at weblogic.t3.srvr.T3Srvr.initialize(T3Srvr.java:589)
at weblogic.t3.srvr.T3Srvr.run(T3Srvr.java:277)
at weblogic.Server.main(Server.java:32)
Please provide some help.

-Michael