How to ping a client using java

Question

i got a problem, can any body help me regarding this matter. Problem is that i want to maintain a list of all the systems that are connected to server and this list is to be maintained using java, as i m building an appication in java where i need this list. Overview of the application is that i m making a PC reservation system. Database of the system will be maintained on the server and all PCs will be linked to it using RMI. For making reservation of different PCs, there must be a list of all working PCs so that selection can be made to reserve a PC. Problem is that how to maintain that list, plus continuous update this list so that if a PC stops working/breaks down, it can be removed from the list. Simple solution to this is to ping each PC after fixed time interval, but how to ping using java ??? i m usgin Microsoft Visual J++ 6.0 for developing my application, and this application will be runnig on Microsoft Windows 2000 operating system, but currently, i m in Windows 98 enviornment.

Answer 1

The 1.4 API actually provides a Runtime.exec(String) but if you want to provide a String array, you can do that as well. None of the exec are static, you need to obtained a reference to the Runtime through the static method getRuntime(). So the exact call looks this way:
Runtime  rt = Runtime.getRuntime();   // you probably want to obtain this REferance only once
Process p = rt.exec(new String[] {"ping", target}); // yes, target is the IP or DNS name of the machine you want to ping