How to keep a java program running during error

Question

I am trying to make a java remote control progam, accesing it via a client, this is some code from the server. I am new to programming, and i would like some help. I want my server to keep running -> problem is, that when i assign a string value to CmdMenuDecision , the server crashes. Any way around it? I also get memory leak at ,, int CmdMenuDecision = new Scanner(System.in).nextInt(); ,, , i use @SuppressWarnings("resource") and i'm not sure if it's good or not.

private static Scanner SCANNER = new Scanner(System. in );
private String command1;
private String command2;
private String command3;
private String command4;

public void runtimeChoice() {
    System.out.println("what do you want to do? 1. Execute CMD Command");
    int CmdMenuDecision = new Scanner(System. in ).nextInt();
    switch (CmdMenuDecision) {
        case 1:
            CMDCommand();
            break;
        default:
            System.out.println("No valid answer");
            break;
    }
    private void CMDCommand() {
        System.out.println("CMD is working!");
        Runtime rt = Runtime.getRuntime();
        try {
            System.out.println("Insert desired command");
            command1 = CmdCommand.nextLine();
            command2 = CmdCommand.nextLine();
            command3 = CmdCommand.nextLine();
            command4 = CmdCommand.nextLine();
            rt.exec(new String[] {
                "cmd.exe", "/c", /*"start",*/
                command1, command2, command3, command4
            });
            System.out.println("Command: " + command1 + " " + command2 + " " + command3 + " " + command4 + " executed succesfully");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

Mohammed Aouf Zouag · Accepted Answer · 2015-12-12 22:39:12Z

1

Change

int CmdMenuDecision = new Scanner(System.in).nextInt();

to

boolean flag = false;

do {
    try {
        int CmdMenuDecision = new Scanner(System.in).nextInt();
        flag = true; // If the execution flow reached this line then that means that the user input was correct; break the loop.
    }
    catch(InputMismatchException e) {
        System.out.println("Invalid input, try again.");
    }
}while(!flag);

This will make sure that you get an Integer input for the CmdMenuDecision variable.

Entering a String when the Scanner is expecting an int will throw an InputMismatchException; you need to handle it.

edited Dec 12, 2015 at 22:39

answered Dec 12, 2015 at 22:34

Mohammed Aouf Zouag

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