java.lang.ArrayIndexOutOfBoundsException object array

Question

Hi I am trying to create a program that collects tasks from a database and displays them for editing. There is an issue that I am not sure how to resolve.

I want to load the several task objects with info from the database. The error only shows up when the program is actually ran.

This is the error:

Please enter a corresponding number: 2
This works? 1
5.6.25-log
This works? 2
This works? 3
This works? 4
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 1
at mytaskapp.DatabaseConnectTaskSelect.Connect(DatabaseConnectTaskSelect.java:65)
at mytaskapp.Display.TaskOutput(Display.java:175)
at mytaskapp.Display.StartScreen(Display.java:51)
at mytaskapp.MyTaskApp.main(MyTaskApp.java:16)
Java Result: 1
BUILD SUCCESSFUL (total time: 3 seconds)

My code is

public static void Connect()
{
    Connection con = null;
    Statement st = null;
    ResultSet rs = null;
    Statement stu = null;
    ResultSet rsu = null;
    PreparedStatement pst = null;

    String url = "jdbc:mysql://localhost:3306/tasks";
    String user = "root";
    String password = "cinder";        

    try {
        int index = 1;            
        TaskObject[] task = new TaskObject[index];
        System.out.println("This works? 1");
        con = DriverManager.getConnection(url, user, password);
        st = con.createStatement();
        rs = st.executeQuery("SELECT VERSION()");

        if (rs.next()) {
            System.out.println(rs.getString(1));
        }

        System.out.println("This works? 2");
        pst = con.prepareStatement("SELECT mainTaskString, timeCreated, dateCreated, timeDue, dateDue, "
                                 + "notes, project, catagory, taskLength, priority, remind1TimeDue, remind1DateDue, "
                                 + "remind2TimeDue, remind2DateDue FROM usertasks");

        rsu = pst.executeQuery();

        System.out.println("This works? 3");
        while (rsu.next()) {
            index = 1;
            //task[index] = new TaskObject(index);
            System.out.println("This works? 4");
            task[index].setTask(rsu.getString("mainTaskString"));
            System.out.println("This works? 4.1");
            task[index].setDateCreated(rsu.getString("timeCreated") + " " + rsu.getString("dateCreated"));
            System.out.println("This works? 4.2");
            task[index].setDateDue(rsu.getString("timeDue") + " " + rsu.getString("dateDue"));
            System.out.println("This works? 4.3");
            task[index].setNotes(rsu.getString("notes"));
            task[index].setProject(rsu.getString("project"));
            task[index].setCatagory(rsu.getString("catagory"));
            task[index].setTaskLength(rsu.getInt("taskLength"));
            task[index].setPriority(rsu.getInt("priority"));
            task[index].setRemind1DateDue(rsu.getString("remind1TimeDue") + " " + rsu.getString("remind1DateDue"));
            task[index].setRemind2DateDue(rsu.getString("remind2TimeDue") + " " + rsu.getString("remind2DateDue"));

            System.out.println("This works? 5");
            System.out.println("Your Task: " + task[index].getTask() + "\n" + " Date Created: " + task[index].getDateCreated() + " Date Due: " +  task[index].getDateDue() + 
                               " Your Notes: " +  task[index].getNotes() + "\n" + " Project: " + task[index].getProject() + " Catagory: " +  task[index].getCatagory() + " The minutes needed to complete: " +  task[index].getTaskLength() +
                               " Priority: " + task[index].getPriority() +  " Reminder 1: "  + 
                               task[index].getRemind1DateDue() +  " Reminder 2: "  +  task[index].getRemind2DateDue() + "\n");
            System.out.println("This works? 6");
            //index++;
        }

Indeed - please provide a *short* but complete program demonstrating the problem. At the moment you're missing a crucial part (the value you're assigning to `index`) but you've got a lot of irrelevant JDBC code. — Jon Skeet, Jun 09 '15 at 05:42
You are creating array TaskObject[] task of size 1. So when your query returns 1+ records, the ArrayIndexOutOfBoundException is being thrown. You need to increase the array size or instead use an ArrayList. — AmolB, Jun 09 '15 at 05:44
Please clarify what you mean by "complete". I fixed the index part. it gives the same error. — Josiah L., Jun 09 '15 at 05:47
create an object of TaskObject before storing it in array - task[index] = new TaskObject(); — Arjit, Jun 09 '15 at 05:50
I add changed it but it just gives me the NullpointerException. int index = 1; TaskObject[] task = new TaskObject[1000]; System.out.println("This works? 1"); — Josiah L., Jun 09 '15 at 05:57

score 2 · Accepted Answer · edited May 23 '17 at 12:14

You can define size of Array only once. So make sure you define it proper otherwise it will throw ArrayIndexOutOfBoundsException when you try to put values more then specified in the size.

In your code you have specified size as 1. So when you try to put more then 1 value in your task array, you will get this exception.

So make sure you specify enough size say 50.

But I would recommend to use List instead of Array, as it gives flexibility automatically increase size without specifying size. You can refer Array or List in Java.

You can make following changes in your code

Declare taskList instead of task array.

List<TaskObject> taskList = new ArrayList<TaskObject>();

In while loop create object of TaskObject, set values into it and then add it to taskList.

TaskObject taskObject = null;
while (rsu.next()) {
    taskObject = new TaskObject();

    taskObject.setTask(rsu.getString("mainTaskString"));
    //set remaining value

    //Add taskObject in List
    taskList.add(taskObject);
}

score 0 · Answer 2 · answered Jun 09 '15 at 06:07

    int index = 1;            
    TaskObject[] task = new TaskObject[index];

This will create the array of the object of type TaskObject with the size 1. That means it can have only task[0]. If you give task[1] it is array out of bound.

So in the while loop it should be (according to your exp)

  index = 0;
        System.out.println("This works? 4");
        task[index].setTask(rsu.getString("mainTaskString"));

If your query is returning fixed number of rows then it is advisable to use array else use arraylist.

java.lang.ArrayIndexOutOfBoundsException object array

2 Answers2