Exception in thread "main" java.rmi.ConnectIOException: non-JRMP server at remote endpoint
at sun.rmi.transport.tcp.TCPChannel.createConnection(TCPChannel.java:248)
at sun.rmi.transport.tcp.TCPChannel.newConnection(TCPChannel.java:202)
at sun.rmi.server.UnicastRef.invoke(UnicastRef.java:129)
at Main_Stub.doIt(Unknown Source)
at Main.main(Main.java:11)
result: Failed. Execution failed: exit code 1

The failure is quite rare. I think I've seen it only once. The code in question exports an object and *immediately* (on the same thread) makes a call to it. It may be a race condition where exportObject() returns before the object has been fully exported. If so, this probably almost never happens in practice, as the stub from an exported object is usually passed to another JVM (e.g., a registry) before any call on it is actually made.