Why do I get an 'ArrayIndexOutOfBoundsException' error?

Question

I'm new to Java programming.

Can someone assist me with the following code:

 public class RandomSeq { public static void main(String[] args) { // command-line argument int N = Integer.parseInt(args[0]); // generate and print N numbers between 0 and 1 for (int i = 0; i < N; i++) { System.out.println(Math.random()); } } } 

I receive the following error message when trying to compile:

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 0

Thank you in advance.

[1] I use a 64-bit Java 8 (Update 25) SE implementation, using a 64-bit Eclipse IDE for Java Developers (v. 4.4.1).

Answer 1

If you run your main() without giving argument list( String[] args ) it will take args as empty.

So, the index 0 is not a valid index, since args is empty.

int N =Integer.parseInt(args[0]);// this cause ArrayIndexOutOfBoundsException

How to set argument for main() in Eclipse.? Read from here .

Answer 2

it's because args is empty :

public class RandomSeq {
    public static void main(String[] args) {
        // command-line argument
        if (args.length > 0) {
            int N = Integer.parseInt(args[0]);

            // generate and print N numbers between 0 and 1
            for (int i = 0; i < N; i++) {
                System.out.println(Math.random());
            }
        }
        else {
            System.out.println("args is empty");
        }
    }
}

Answer 3

Run-> Run Configurations->Arguments->Enter your arguments separated by space->Apply->Run

确保在运行配置下的“主要”选项卡下选择了正确的项目名称及其主要方法

Answer 4

Its because You're not passing any Value So args[] is Empty..
When You are using Eclipse, go to Run->Run Configuration-> Arguments , Pass some value.
Your code runs perfectly fine..!!