JAVA Question: Index 130 out of bounds for length 130

Question

I am running the following code and I keep getting the following error:

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: Index 130 out of bounds for length 130 at Datachange.init(Datachange.java:55) at Datachange.main(Datachange.java:38)

I am trying to read a file and manipulated into an output and its seems that its not reading the file well. '

import java.io.*;

public class Datachange
{
    public class variables
    {
    private char [] body;
    private int ID;
    private int population;
    private int populationchilds;
    private int populationchildspoverty;
    private double populationchildpovertypercent;

        variables(char [] input)
        {
        body = input;

        char[] stateID = java.util.Arrays.copyOfRange(body,0,2);
        ID = Integer.parseInt(new String(stateID).trim());

        char[] totalpopulation  = java.util.Arrays.copyOfRange(body,83,90);
        population = Integer.parseInt(new String(totalpopulation).trim());

        char [] childpopulation = java.util.Arrays.copyOfRange(body,92,99);
        populationchilds = Integer.parseInt(new String(childpopulation).trim());

        char [] povertychilds = java.util.Arrays.copyOfRange(body,101,108);
        populationchildspoverty = Integer.parseInt(new String(povertychilds).trim());
        }
    }




    public static void main(String[] args)
    {
        Datachange DS = new Datachange();
        DS.init();
    }


    public void init()
    {
        variables dataframe[] = new variables[13286];
        try (FileReader inputDataframe = new FileReader("file.txt"))
        {
            int c;
            int i = 0;
            int j = 0;
            char variableinput [] = new char[130];

            while((c = inputDataframe.read())!=-1)
            {

                    variableinput[i] = (char) c;
                    i++;


                if(c==10)
                {
                    dataframe[j] = new variables(variableinput);
                    j++;
                    i = 0;
                }
            }
        }
        catch(IOException except)
        {
            System.out.println("There is Input/Output Error:" + except.getMessage());
        }
        this.newdata(dataframe);
    }


    public variables[] newdata(variables[] dataset)
    {
        variables[] newdata=new variables[57];

        try (BufferedWriter outData = new BufferedWriter(new
                FileWriter("manipulatedfile.txt")))
        {
            int stateID = 1; //First ID
            int statePop= 0;
            int stateChdPop=0;
            int stateChdPovertyPop=0;

            for(int i=0;i<dataset.length;i++)
            {
                if (dataset[i].ID == stateID)
                {
                    statePop += dataset[i].population;
                    stateChdPop += dataset[i].populationchilds;
                    stateChdPovertyPop += dataset[i].populationchildspoverty;
                }

                else
                {
                    double stateChdPovertyPopPercent=0;
                    if (stateChdPop != 0)
                    {
                        stateChdPovertyPopPercent = (double)
                                stateChdPovertyPop/stateChdPop * 100;
                        int z = 12;
                    }

                    else
                    {
                        stateChdPovertyPopPercent = 0;
                    }

                    outData.append(stateID + "\t" + statePop + "\t" +
                            stateChdPop + "\t" + stateChdPovertyPop+
                            "\t" + stateChdPovertyPopPercent + "\n");

                    statePop = 0;
                    stateChdPop = 0;
                    stateChdPovertyPop = 0;
                    i--;
                    stateID++;
                }
            }
        }
        catch(IOException except)
        {
            System.out.println("I/O Error:" + except.getMessage());
        }

        int x = 12;
        return newdata;
    }
}
'

Answer 1

It is reading the file just fine, otherwise it would throw an IOException instead of an ArrayIndexOutOfBoundsException.

From the Oracle Documentation about ArrayIndexOutOfBoundsException:

Thrown to indicate that an array has been accessed with an illegal index. The index is either negative or greater than or equal to the size of the array.

That happens in your init() method if I am not mistaken. You have an array that has a limit of 130 and trying to get the element at index 130+ (because arrays start counting at 0) will give you that exception.

variableinput[130] will throw it.