Why does my program keeps giving me an ArrayIndexOutOfBoundsException even tough I haven't got one

Question

I was recently trying to build a program that takes two inputs and checks whether they are equally represented in other bases(bases are up till 20). But i keep getting the index out of bounds exception at line number 28...what to do?

For example: 12(base 10) = 5(base 3) [both are represented as '12' in their respective bases.]

import java.util.Scanner;
import java.util.Arrays;
class Bases
{

    public static void main()
    {
        Scanner sc = new Scanner(System.in);
        System.out.println("Enter Two Numbers: ");
        int a  = sc.nextInt();
        int b = sc.nextInt();
        System.out.println("Thank You for inputting the numbers!");

        String basea[] = new String[20];
        String baseb[] = new String[20];

        int i=0 , j=0;
        for( i=0;i<20;i++)
        {
            basea[i] = convert(a,i+1);
            baseb[i] = convert(b,i+1);
        }

        for(i=0;i<=19;i++)
        {
            for(j=0;i<=19;j++)
            {
                if(basea[i].equals(baseb[j])) 
                {//this is where the exception keeps popping

                    break ;
                }
            }
        }
        if(i!=20){ 
            if(i==0){
                i=9; 
                System.out.println(a+"(base "+(i+1)+") ="+b+"(base "+(j+1)+")");
            }
            else 
                System.out.println(a+"(base "+(i+1)+") ="+b+"(base "+(j+1)+")");
        }
        else System.out.println("Numbers dont match at all till base 20!!");
    }

    private static String convert(int number,int base)
    {

        return Integer.toString(number,base);
    }

}

Answer 1

for(j=0;i<=19;j++)

以上循环应为j <= 19

for(j=0;j<=19;j++)

Answer 2

for(i=0;i<=19;i++)
{
    for(j=0;i<=19;j++)
    {
        if(basea[i].equals(baseb[j])) 
        {//this is where the exception keeps popping

            break ;
        }
    }
}

You can see in this original snippet of code you had a typo

for(i=0;i<=19;i++)
{
    for(j=0;i<=19;j++) <---- the middle parameter is 'i' instead of 'j'
    {

Simply fix this by fixing your typo, and if you want to you can make it <20 for some added neatness.

for(i=0;i<20;i++)
{
    for(j=0;j<20;j++)
    {