Errata

This isn't an errata per se, but Java 1.3 changed the way in which certain things work, and we're getting a few questions about it. So...

In 1.3, the command to start rmid has changed to rmid
-J-Djava.security.policy=/files/jini1_0/java.policy.all

text reads

"...in all other areas of Java, objects are passed strictly by reference.
Remote objects, on the other hand, are passed by reference..."

Should this be "by value"? If not, then what does this mean?

server% javac CompexNumber.java..........

should read:

server% javac ComplexNumber.java..........

In Example 3-3, it is written that the ConvertClient code from Example 3-1

"To mark a service object as inactive, call it's inactive() method" should
read "To mark a service object as inactive, call the
Activable.inactive(ActivationID) method [because it's a static method] and
supply the id of the object". It's a major difference, because you don't need a
reference to the object to do this.

The text refers to the interface "java.rmi.activation.Unreferenced". It should
read: "java.rmi.server.Unreferenced".

The service Finder for example 4-1 do not work in the actual printed version. Because the service finder seems to wait BEFORE the lookup services are discovered.

So I've make a few change to resolve this :
- First I'va applied a limitation for the waiting on the getObject() method (in the ServiceFinderClass).

public synchronized Object getObject()
{
while (returnObject.size()==0)
{
try{ wait(500);
System.out.println("getObject(), Waiting...");
}
catch (InterruptedException e) {}
}
return ((ServiceItem)returnObject.elementAt(0)).service;
}

-And I've modified a bit the ConvertClient.java file, so the main method instanciate a ConvertClient class, and this class wait for the discovery service.

public class ConvertClient
{
public void ConvertClient () {}

public void working_c() throws Exception
{
System.setSecurityManager(new RMISecurityManager());

ServiceFinder sf=new ServiceFinder(ConvertService.class);
ConvertService cs;
System.out.println(" Creation ConverService");
boolean done=false;
while(!done)
{
try {wait(1000);}
catch (Exception e) { System.out.println(" error : "+e);}

cs=(ConvertService)sf.getObject();
try { System.out.println(cs.convert(18));
done=true;}
catch (RemoteException e) { System.out.println(" Remote Error : "+e);
sf.errored(cs);}
}
}
public static void main(String args[]) throws Exception
{
ConvertClient cc=new ConvertClient();
cc.working_c();
}
}

On my computer (win98), this example was not working. Apparently, the lookup
method queries only known lookup services, so when called right away, it has
not yet established contact to any, and the lookup method will block forever.
A Thread.sleep(2000) directly before the "lookup(...)" call fixes this problem.