Error : Exception in thread "main" how can it be fixed?

[bsegvic]

import java.util.HashMap;

public class zadatak {

public static void main(String[] args) {
String input = args[0];

String [] numbers = input.split("_");

HashMap<String, Integer> frequency = new HashMap<String, Integer>();

for(int i = 0; i < numbers.length; i++){
if(frequency.containsKey(numbers[i])){
Integer value = frequency.get(numbers[i]);
value++;
frequency.put(numbers[i], value);
}
else{
frequency.put(numbers[i], 1);
}
}

for(String key : frequency.keySet()){
System.out.print(key + "_" + frequency.get(key) + " ");
}
}

}

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 0
at zadatak.main(zadatak.java:6)

After running this program I keep getting this error msg,can u please advice me, how can it be fixed?

Thanks!

[JosAH]

Did you write that program yourself? If so, you must've forgotten that it needs (at least) one command line argument to run.

kind regards,

Jos

[AeneasTroy]

Yeah,

Example

COMMAND LINE

C:\Folder> myProgram.exe -x dosomthing

In this example, "-x" and "dosomething" get stored in the args[] array. So you would have arg[0] and arg[1]

If you were to just run myProgram.exe with no arguments, the args[] array would be empty. It wouldn't have anything at arg[0]