Thread (Runnable) and action requests

[Richard A. DeVenezia]

I am trying to implement a Runnable that will do various actions by way of
methods.
The design is a little bass-ackwards because the eventual user will
'bridging' into the JVM (from app ABC) through a sub-optimal jni adapter
that can receive new references, but not receive object references in return
and loses the new references between the 'tasks' of ABC.

Q: how bad is the 'Service' design ?
Q: is there something better than could be done in the run() ? (Such as
yield or wait)

Is
while(!end) {} just as bad as
while(!end) { Thread.yield(); }

Thanks.

//-------------

public class Service implements Runnable {
public void run () {

private boolean end = false;
private int status = 0;

public void end () { this.end=true; }

System.out.println ("Running");
try {
while (!end) { Thread.sleep(50) }
}
catch (InterruptedException e) {}
System.out.println ("Done");
}

public int getStatus () {
return this.status;
}

public void connect () {
status = 100;
return 1;
}

public int obtainX () {
status = 200;
return 2;
}

public void setA (int X, String s)
{
// some feature S of an object
// functionally derived from X
// is set to s
status = 300;
}
}

//-------------

public class ServiceAdapter {

private static Service service = null;
private static Thread thread = null;

ServiceAdapter () {
if (service != null) return;
service = new Service();
thread = new Thread (service);
thread.start();
}

void connect () {
service.connect();
}

int obtainX () {
return service.obtainX ();
}

void setA (int X, String s) {
service.setA (X,s);
}

void end () {
service.end();
}
}

//-------------
// Some pseudo-jni adapted application does the equivalent of
//-------------


ServiceAdapter jsa = new ServiceAdapter();
jsa.connect();
jsa = null;

jsa = new ServiceAdapter();
int x = jsa.obtainX();
jsa.setA (x, "foobar");
jsa = null;

jsa = new ServiceAdapter();
jsa.end();