CODEWITHSUNDEEP
java
salpenza
salpenza

Reputation: 37

Unknown cause of: java.lang.ArrayIndexOutOfBoundsException: Index 0 out of bounds for length 0 from Command Line

For some reason, I am getting this error and I am very confused at this point. How can I correct this problem?

public static void main(String[] args) throws FileNotFoundException {
    Memory myMemory = new Memory();
    File file = new File(args[0]);
    myMemory.fileParser(file);
}

This is my error:

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: Index 0 out of bounds for length 0
        at Memory.main(Memory.java:262)

Upvotes: 1

Views: 1339

Answers (2)

EricHo
EricHo

Reputation: 183

Have you passed any arguments to the main method when you run the programme?

You have to explicitly pass strings to the args in main(String[] args), otherwise args[0] will throw an exception

How to pass an arg in eclipse: Invoking Java main method with parameters from Eclipse

Upvotes: 0

Stephen C
Stephen C

Reputation: 719386

It is clear that you have run the program without supplying any command line arguments. As a result, the args arraay has length zero. Your code is not designed to cope with it, and it is trying to use an argument taken from a position beyond the end of the array.

There are two parts to the solution:

  1. You need to supply arguments. For example, if you are running the program from the command line:

      $ java name.of.your.mainclass filename

  2. You need to modify the program so that it detects that it has been called without arguments and prints an error message. For example:

    public static void main(String[] args) throws FileNotFoundException {
    if (args.length != 1) {
        System.err.println("Filename argument missing.")
        System.err.println("Usage: <command> <filename>");
        System.exit(1);
    }

    Memory myMemory = new Memory();
    File file = new File(args[0]);
    myMemory.fileParser(file);
}

Upvotes: 1

Related Questions