java.rmi.ServerError: Error occurred in server thread; nested exception is:

Question

I'm upgrading jdk from 8 to 10 and get an exception:

    java.rmi.ServerError: Error occurred in server thread; nested exception is:
    java.lang.NoClassDefFoundError: java/sql/Timestamp at     java.rmi/sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:388)
at java.rmi/sun.rmi.transport.Transport$1.run(Transport.java:200)
at java.rmi/sun.rmi.transport.Transport$1.run(Transport.java:197)
at java.base/java.security.AccessController.doPrivileged(Native Method) 
at java.rmi/sun.rmi.transport.Transport.serviceCall(Transport.java:196)
at java.rmi/sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:562)
at java.rmi/sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:796)

The rmiregistry can be started correctly, but my RMI server program can't bind my object. Why?