private void runCommand()

in bookkeeper-server/src/main/java/org/apache/bookkeeper/util/Shell.java [106:210]
92 lines of code
18 McCabe index (conditional complexity)

    private void runCommand() throws IOException {
        ProcessBuilder builder = new ProcessBuilder(getExecString());
        Timer timeOutTimer = null;
        ShellTimeoutTimerTask timeoutTimerTask = null;
        timedOut = new AtomicBoolean(false);
        completed = new AtomicBoolean(false);

        if (environment != null) {
            builder.environment().putAll(this.environment);
        }
        if (dir != null) {
            builder.directory(this.dir);
        }

        if (Shell.WINDOWS) {
            throw new IOException("Windows is not supported.");
        } else {
            process = builder.start();
        }

        if (timeOutInterval > 0) {
            timeOutTimer = new Timer("Shell command timeout");
            timeoutTimerTask = new ShellTimeoutTimerTask(this);
            //One time scheduling.
            timeOutTimer.schedule(timeoutTimerTask, timeOutInterval);
        }
        final BufferedReader errReader = new BufferedReader(new InputStreamReader(process.getErrorStream(),
                StandardCharsets.UTF_8));
        BufferedReader inReader = new BufferedReader(new InputStreamReader(process.getInputStream(),
                StandardCharsets.UTF_8));
        final StringBuffer errMsg = new StringBuffer();

        // read error and input streams as this would free up the buffers
        // free the error stream buffer
        Thread errThread = new Thread() {
            @Override
            public void run() {
                try {
                    String line = errReader.readLine();
                    while ((line != null) && !isInterrupted()) {
                        errMsg.append(line);
                        errMsg.append(System.getProperty("line.separator"));
                        line = errReader.readLine();
                    }
                } catch (IOException ioe) {
                    LOG.warn("Error reading the error stream", ioe);
                }
            }
        };
        try {
            errThread.start();
        } catch (IllegalStateException ise) {
        }
        try {
            parseExecResult(inReader); // parse the output
            // clear the input stream buffer
            String line = inReader.readLine();
            while (line != null) {
                line = inReader.readLine();
            }
            // wait for the process to finish and check the exit code
            exitCode = process.waitFor();
            try {
                // make sure that the error thread exits
                errThread.join();
            } catch (InterruptedException ie) {
                Thread.currentThread().interrupt();
                LOG.warn("Interrupted while reading the error stream", ie);
            }
            completed.set(true);
            //the timeout thread handling
            //taken care in finally block
            if (exitCode != 0) {
                throw new ExitCodeException(exitCode, errMsg.toString());
            } else {
                String errMsgStr = errMsg.toString();
                if (!errMsgStr.isEmpty()) {
                    LOG.error(errMsgStr);
                }
            }
        } catch (InterruptedException ie) {
            Thread.currentThread().interrupt();
            throw new IOException(ie.toString());
        } finally {
            if (timeOutTimer != null) {
                timeOutTimer.cancel();
            }
            // close the input stream
            try {
                inReader.close();
            } catch (IOException ioe) {
                LOG.warn("Error while closing the input stream", ioe);
            }
            if (!completed.get()) {
                errThread.interrupt();
            }
            try {
                errReader.close();
            } catch (IOException ioe) {
                LOG.warn("Error while closing the error stream", ioe);
            }
            process.destroy();
            lastTime = System.currentTimeMillis();
        }
    }