Process Builder Incrementing Error

I have written a program to monitor the status of some hard drives attached to a RAID on Linux. Through this program I execute several command line commands. An interesting error occurs though....the program runs for a good three minutes before it seems that it can no longer correctly execute the command it had been previously executing (for many iterations).

It spits out an array index error (my variable driveLetters[d]) because it appears to miss the drive somehow (even though it found it hundreds of times before).

Other things to note...if I tell it to reset int "d" to "0" if it exceeds the number of drives...the program won't crash and instead will just become stuck in an infinite loop. Also, the time at which the program crashes varies. It doesn't appear to crash after a set number of intervals. Finally, I don't ge开发者_StackOverflowt any kind of memory leak errors.

Here is some of code that should reveal the error:

public static void scsi_generic() throws IOException, InterruptedException
{
    int i =0;
    int d =0;

    int numberOfDrives = 8;

    char driveLetters[] = {'b','c','d','e','f','g','h','i','j','k','l','m'};

    String drive = "";

    while (i <= numberOfDrives)
    {
        System.out.println("position 1");
        List<String> commands = new ArrayList<String>();
        commands.add("cat");
        commands.add("/sys/class/scsi_generic/sg"+i+"/device/sas_address");


        SystemCommandExecutor commandExecutor = new SystemCommandExecutor(commands);
        int driveFound = commandExecutor.executeCommand();


        if (driveFound == 0)
        {
            System.out.println("Folder: sg" + i + " was found." );
            StringBuilder stdout = commandExecutor.getStandardOutputFromCommand();
            String data = stdout.toString();
            String sas = data.substring(11,12);
            int sasA = Integer.parseInt(sas,16);


            boolean matchedSG = false;

            while (matchedSG == false)
            {
                System.out.println("position2");      
                List<String> lookSD = new ArrayList<String>();
                lookSD.add("test");
                lookSD.add("-d");
                lookSD.add("/sys/class/scsi_generic/sg"+i+"/device/block:sd" + driveLetters[d]);
                SystemCommandExecutor commandSearch = new SystemCommandExecutor(lookSD);
                int sdFound = commandSearch.executeCommand();
                StringBuilder stdout3 = commandSearch.getStandardOutputFromCommand();
                StringBuilder stderr = commandSearch.getStandardErrorFromCommand();
                String sdFound2 = stdout3.toString();

                if (sdFound == 0)
                {
                    matchedSG = true;
                    System.out.println("Found the SD drive.");
                    drive = "sd"+driveLetters[d];
                    System.out.println(sasA);
                    hdsas.set(sasA , sas);
                    d = 0;
                    i++;
                    loadDrives(drive , sasA);
                }
             /*   else if (sdFound != )
                {
                    System.out.println("Error:" + sdFound);
                    System.out.println(d+  " "+ i);   
                }
                */
                else if ( d >= 8)
                {
                    System.out.println("Drive letter: " + driveLetters[d]);
                    System.out.println("Int: " + i);
                    // System.out.println(sdFound2);
                    System.out.println("sd error: "+ sdFound);
                    // System.out.println(stderr);
                    //System.out.println(sdFound2 + " m");
                }
                else 
                {
                    d++;
                }
            }
        }
        else 
        {
            System.out.println("Folder: sg" + i + " could not be found.");
            i++;
        }

        d =0;
    }
 }

Any help or suggestions would be awesome! Thanks.

EDIT:

The solution I found was to use the java library for testing if a directory exists rather than doing it through the linux command line.

Ex:

File location = new File("directory");
if (location.exists())
{

}

No idea why it works and doesn't crash, where as the linux command line did after a short period of time, but it does.

This is no direct answer to your question, but it still might help you:

I often have to find bugs in code like yours (very long methods with "global" variables, that is, variables declared at the beginning of a method and used all over then). Just by refactoring the code properly (short methods with a single purpose each), the cause of the bug becomes immediately visible to me and is fixed within a second (while the refactoring itself takes much longer).

I guess that's what everyone trying to offer you help is doing anyway: Refactor your code (probably only in one's head) so that is (much) more easy to understand what's going on.

The solution I found was to use the java library for testing if a directory exists rather than doing it through the linux command line.

Ex:

File location = new File("directory");
if (location.exists())
{

}

No idea why it works and doesn't crash, where as the linux command line did after a short period of time, but it does.