Problem with statement "Integer.parseInt(args[0]);

[peterfgoossens@gmail.com]

See below. Below the class is the error message at running.

I use Netbeans. Saving the class goes ok. But at running it gives the error message. The problem seems to be at the statement "int peter3 = Integer.parseInt(agrs[0]);"



class PeterTry1 {
public static void main(String[] args) {
String peter1 = "p";
System.out.println(peter1);

int peter3 = Integer.parseInt(args[0]);
float peter4 = peter3;
Float peter5 = new Float(peter4);
Integer peter6 = peter5.intValue();
System.out.println(peter6);

}
}


run:
p
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 0
at PeterTry1.main(PeterTry1.java:6)
Java Result: 1
BUILD SUCCESSFUL (total time: 0 seconds)

[eRaaaa]

Your args array is empty. How do you start your program? Have you set the run arguments in netbeans?
Run -> Set project configuration -> Run -> Input a argument ....

[Fubarable]

Line 6 will tell you where the error is occurring. You appear to be trying to use an array that has no members, whose size is 0. The only array here is the args array. You seem to be trying to get the command line parameters in this program but have neglected to run it with command line parameters.

Solution 1: pass in some parameters when you run this code.

Solution 2: Try to understand what the error message is telling you for often the answer is right there.

[peterfgoossens@gmail.com]

Thanks for the hints!! I had entered "10", when I now entered just a one digit argument, it worked fine. Can that have been the reason?

[JosAH]

Thanks for the hints!! I had entered "10", when I now entered just a one digit argument, it worked fine. Can that have been the reason?

You didn't write that code yourself did you? Otherwise you would've known what that args[0] was for and you wouldn't have been so surprised when the error happened.

kind regards,

Jos

[peterfgoossens@gmail.com]

Correction: I answered too quick. It was not the number of digits. It was choosing "Run Main Project" and not "Run File". I used to use "Run File".

Why is that?

[peterfgoossens@gmail.com]

I did write it myself though. 1) I am probably the newest of all newbies; 2) I didn't understand the runtime error (and do still not understand it); 3) but by running it as "main project" and not as "file" the code accepts any type of argument.

[Tolls]

Correction: I answered too quick. It was not the number of digits. It was choosing "Run Main Project" and not "Run File". I used to use "Run File".

Why is that?

Run File is the equivalent of "java MyProg"...no extra arguments.
Run Main Project runs the setup defined in the Run Main Project bit, which includes a section for adding arguments.

[JosAH]

I did write it myself though.

I've got it: you fell asleep with your nose on the keyboard and accidentally typed:

int peter3 = Integer.parseInt(args[0]);

kind regards,

Jos ;-)