Scheduler Issue

[ercfrtz]

I do not know how to do what I am trying to do. I have an array of images that move across the screen. What I want to do is periodically increase this array and add a new element to it. The code from the 2 classes below shows how I attempted to do that. I was reserved doing it this way as I figured it wouldn't like multiple things trying to access the same array. When I ran the program it crashed when it tried to increase the array size, so my assumption was correct. My issue is, I am rusty on my Java and cannot think of a way to get around this.

import java.util.*;
import java.awt.*;
import java.awt.image.BufferedImage;
import javax.swing.*;
import javax.imageio.*;
import java.lang.Math;
import java.io.*;
import java.util.concurrent.*;
import java.util.concurrent.TimeUnit.*;
 
public class CellAttack extends JPanel
{
 
public static Rectangle screen, bounds;
public static JFrame frame;
public static ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(1);
public static RedBloodCell[] redCellArray = new RedBloodCell[40];
public static interactiveParticle[] IPArray = new interactiveParticle[2];
public static Random RG = new Random();
public BufferedImage background = null;
public static CellAttack panel;
 
  public CellAttack()
  {
    super();
    screen = new Rectangle(0, 0, 800, 600);
    bounds = new Rectangle(0, 0, 800, 600); 
    for(int i = 0; i < redCellArray.length; i++)
    {
        redCellArray[i] = new RedBloodCell(RG.nextInt(bounds.width+1),RG.nextInt(bounds.height-130)+50,(RG.nextInt(5)+1),bounds.width,bounds.height-130);
    }
    for(int m = 0; m < IPArray.length; m++)
    {
        IPArray[m] = new interactiveParticle(RG.nextInt(bounds.width+1),RG.nextInt(bounds.height-130)+50,(RG.nextInt(5)+1),bounds.width,bounds.height-130,RG.nextInt(3)+1,panel);
    }
    frame = new JFrame("Cell Attack");
    try
    {
        background = ImageIO.read(new File("background.png"));
    }
    catch(IOException e){}
  }
 
  public void paintComponent(Graphics g)
  {
    bounds = g.getClipBounds();
    g.clearRect(screen.x, screen.y, screen.width, screen.height);
    g.drawImage(background,0,0,this);
    for(int k = 0; k < redCellArray.length; k++)
    {
        g.drawImage(redCellArray[k].img, redCellArray[k].x, redCellArray[k].y, this);
    }
    for(int n = 0; n < IPArray.length; n++)
    {
        g.drawImage(IPArray[n].img, IPArray[n].x, IPArray[n].y, this);
    }
  }
 
  public void increaseIPArray()
  {
      interactiveParticle[] tempIPArray = new interactiveParticle[IPArray.length+1];
      for(int q = 0; q < IPArray.length; q++)
      {
          tempIPArray[q] = IPArray[q];
      }
      tempIPArray[IPArray.length] = new interactiveParticle(bounds.width,RG.nextInt(bounds.height-130)+50,(RG.nextInt(5)+1),bounds.width,bounds.height-130,RG.nextInt(3)+1,panel);
      IPArray = tempIPArray;
  }
 
  public static void main(String arg[])
  {
    panel = new CellAttack();
 
    Runnable mover = new Runnable()
    {
      public void run()
      {
        for(int j = 0; j < redCellArray.length; j++)
        {
          redCellArray[j].move();
        }
        for(int p = 0; p < IPArray.length; p++)
        {
          IPArray[p].move();
        }
        frame.repaint();
      }
    };
    scheduler.scheduleAtFixedRate(mover, 0, 20, TimeUnit.MILLISECONDS);
 
    panel.frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    panel.frame.setSize(panel.screen.width, panel.screen.height+22);
 
    panel.frame.setContentPane(panel);
    panel.frame.setVisible(true);
  }
}

import java.util.*;
import java.awt.*;
import java.awt.image.BufferedImage;
import javax.swing.*;
import javax.imageio.*;
import java.lang.Math;
import java.io.*;
 
public class interactiveParticle
{
    public int x, y, width, height, Xstart, Yheight, redCellNum;
    int xVel;
    public Random RG = new Random();
    public BufferedImage img = null;
    public CellAttack CA;
 
    public interactiveParticle(int tempX, int tempY, int tempSpeed, int tempWidth, int tempHeight, int IP, CellAttack tempCA)
    {
        x = tempX;
        y = tempY;
        CA = tempCA;
        try
        {
            img = ImageIO.read(new File("virus"+String.valueOf(IP)+".png"));
        }
        catch(IOException e){}
        xVel = tempSpeed;
        Xstart = tempWidth;
        Yheight = tempHeight;
    }
 
    public void move()
    {
        x-=xVel;
 
        if(x < 0)
        {
            x = Xstart;
            y = RG.nextInt(Yheight)+50;
            xVel = RG.nextInt(4)+1;
            try
            {
                img = ImageIO.read(new File("virus"+String.valueOf(RG.nextInt(3)+1)+".png"));
            }
            catch(IOException e){}
            CA.increaseIPArray();
        }
    }
}