java.lang.Process hang when recursively called

Question

My program recursivly calls the McAfee OnDemad Virusscanner for a specific path. In a loop I fill the path with several files, scan it, remove the files, fill it and so on. After a while the program suddenly hangs and I've no clue for the reason.

        Calendar cl = Calendar.getInstance();
        String cmd="uvscan -v /var/tmp/McAfee/scanFiles/"
        try {   
        long start=cl.getTimeInMillis();
        process = Runtime.getRuntime().exec(cmd, null);
        Worker worker = new Worker(process);
        worker.start(); 
        try {
            LOGGER.debug("Virusscan timeout set to {}ms", timeout);
            worker.join(timeout);
            if (worker.exit != null)
                workerRC=worker.exit;
            else {
                cl = Calendar.getInstance();
                long waitTime=cl.getTimeInMillis()-start;
                throw new TimeoutException("Virusscan timeout after " + waitTime + "ms"); 
            }
            //      else
            //          throw new TimeoutException();
        } catch(InterruptedException ex) {
            worker.interrupt();
            Thread.currentThread().interrupt();
            cl = Calendar.getInstance();
            long waitTime=cl.getTimeInMillis()-start;
            throw new TimeoutException("Virusscan timeout after " + waitTime + "ms"); 
        } 

        File scanLog = new File(ConfigReader.getScanLog());
        if (!ConfigReader.mustKeepScanLog()) scanLog.deleteOnExit();
        LOGGER.debug("ScanLog is: " + scanLog.getPath() + " - RC=" + workerRC);
        BufferedWriter bw = new BufferedWriter(new FileWriter(scanLog));
        BufferedReader stdInput = new BufferedReader(new InputStreamReader(process.getInputStream()));
        // read the output from the command             
        while ((buffer = stdInput.readLine()) != null) {
            inspectScanlog(buffer, workerRC);
            bw.write(buffer+"\n");
            LOGGER.debug("Scan STDOUT: " + buffer);
        }
        BufferedReader stdErr = new BufferedReader(new InputStreamReader(process.getErrorStream()));
        while ((buffer = stdErr.readLine()) != null) {
            LOGGER.debug("Scan STDERR: " + buffer);
        }

        bw.close();

        cl = Calendar.getInstance();
        long waitTime=cl.getTimeInMillis()-start;
        LOGGER.info("Virusscan took " + waitTime + "ms");
        if (workerRC != 0){
            int cc=12;
            ConfigReader.setMaxCC(cc);
            LOGGER.error("RC={} - Virusscan ended with error. CMD=",cc, cmd);
            if (workerRC==13) {
                LOGGER.error("RC={} - The scanner found one or more viruses or hostile objects - such as a Trojan-horse program, joke program, or test file.", cc);
            }
        }
    }
    catch (Exception e) {
        int cc=12;
        ConfigReader.setMaxCC(cc);
        LOGGER.error("RC={} - {}",cc, e.getMessage());
        e.printStackTrace();
    } finally {
        if (process!=null) {
            process.destroy(); 
        }
    }

It looks like a hang of the complete program; even the timeout (240000ms) doesn't match. The GC-log seems kind of interrupted:

258.070: [Full GC [PSYoungGen: 13456K->7362K(85120K)] [PSOldGen: 59271K->60735K(81728K)] 72727K->68098K(166848K) [PSPermGen: 16282K->16282K(30400K)], 0.3019290 secs] [Times: user=0.31 sys=0.00, real=0.31 secs] 264.208: [GC [PSYoungGen: 65466K->8773K(92224K)] 126202K->69581K(173952K), 0.0528360 secs] [Times: user=0.10 sys=0.00, real=0.05 secs] 265.445: [GC [PSYoungGen: 81774K->9133K(92096K)] 142582K->70061K(173824K), 0.0205430 secs] [Times: user=0.03 sys=0.00, real=0.02 secs] 266.916: [GC [PSYoungGen: 82515K->9698K(100096K)] 143443K->70658K(181824K), 0.0189050 secs] [Times: user=0.04 sys=0.00, real=0.02 secs] 267.817: [GC [PSYoungGen: 92311K->1436K(100480K)] 153271K->70986K(182208K), 0.0210400 secs] [Times: user=0.03 sys=0.01, real=0.02 secs] 274.208: [GC [PSYoungGen: 84072K->672K(112256K)] 153622K->71297K(193984K), 0.0029610 secs] [Times: user=0.00 sys=0.00, real=0.00 secs] 275.769: [GC [PSYoungGen: 94880K->500K(112832K)] 165505K->71732K(194560K), 0.0022440 secs]

The uvscan-command has been called 277.609 seconds after program-start.

Could anyone suggest how to get the reason for the hang?

Thanks in advance, Ulrich