RMI server: rmiregistry or LocateRegistry.createRegistry

Question

For RMI on server-side, do we need to start rmiregistry program, or just call LocateRegistry.createRegistry? If both are possible, what are the advant

Answer 1

If we start rmiregistry first, RmiServiceExporter would register itself to the running rmiregistry. In this case, we have to set the system property 'java.rmi.server.codebase' to where the 'org.springframework.remoting.rmi.RmiInvocationWrapper_Stub' class can be found. Otherwise, the RmiServiceExporter would not be started and got the exception " ClassNotFoundException class not found: org.springframework.remoting.rmi.RmiInvocationWrapper_Stub; nested exception is: ..."

If your rmi server, rmi client and rmiregistry can access the same filesystem, you may want the system property to be automatically configured to where the spring.jar can be found on the shared filesystem. The following utility classes and spring configuration show how this can be achieved.

abstract public class CodeBaseResolver { 
  static public String resolveCodeBaseForClass(Class clazz) {
    Assert.notNull(clazz);
    final CodeSource codeSource = clazz.getProtectionDomain().getCodeSource();
    if (codeSource != null) {
      return codeSource.getLocation().toString();
    } else {
      return "";
    }
  }
}

public class SystemPropertyConfigurer {
  private Map systemProperties;
  public void setSystemProperties(Map systemProperties) {
    this.systemProperties = systemProperties;
  }

  @PostConstruct
  void init() throws BeansException {
    if (systemProperties == null || systemProperties.isEmpty()) {
      return;
    }
    for (Map.Entry entry : systemProperties.entrySet()) {
      final String key = entry.getKey();
      final String value = SystemPropertyUtils.resolvePlaceholders(entry.getValue());
      System.setProperty(key, value);
    }
  }
}



  
  
    
      org.springframework.remoting.rmi.RmiInvocationWrapper_Stub
    
  



  
    
  



  
  
  
  

The above example shows how system property be set automatically only when rmi server, rmi client and rmi registry can access the same filesystem. If that is not true or spring codebase is shared via other method (e.g. HTTP), you may modify the CodeBaseResolver to fit your need.