//Server.java
     //ConcurrentMap to hold each client's context
     private final ConcurrentMap<String, RequestContext> ctxs =  Maps.newConcurrentMap();

    //see Tango Java API for deviceManagment
    @DeviceManagement
    private DeviceManager deviceManager;

    //this will be an attribute, each client will see its own value
    @Attribute
    //this method returns client identity from CORBA as String
    public String getClientId() throws Exception {
        //deviceManager exports CORBA's client identity feature
        return ClientIDUtil.toString(deviceManager.getClientIdentity());
    }
 
    //command that returns its result in the format defined in the client's context
    @Command
    public String doJob() throws Exception {
        String clientId = getClientId();
        RequestContext ctx = ctxs.get(clientId);
        switch(ctx.outputType){
            case OutputType.PLAIN:
                return plainResult();
            case OutputType.JSON:
                return jsonResult();
        }
    }

//RequestContext.java
//NOTE this class must be thread safe
@Immutale
public class RequestContext {
        //OutputType is an enum
        public final OutputType outputType;

        public RequestContext(OutputType outputType) {
            this.outputType = outputType;
        }

        /**
         * Creates default context
         */
        public RequestContext() {
            this(OutputType.PLAIN);
        }
    }

// local field to pass clienId across method calls
private String clientId;
    
@AroundInvoke
public void aroundInvoke(InvocationContext ctx){
    clientId = ClientIDUtil.toString(ctx.getClientID());
}

// local field to pass clienId across method calls
private ThreadLocal<String> clientId;
    
@AroundInvoke
public void aroundInvoke(InvocationContext ctx){
    clientId.set(ClientIDUtil.toString(ctx.getClientID()));
}