Insertionsort - Sorting Algorithm - JAVA

Program:
import java.io.*;
class arraylist
{
    private int[] a;
    private int n;
    private int[] temp;
    public arraylist(int x)
    {
        a = new int[x];
        n=0;
        temp = new int[x];
    }
    public void insert(int e)
    {
        n++;
        a[n]=e;
    }
    public void display()
    {
        for(int i=1;i<=n;i++)
        System.out.print(a[i]+" ");
        System.out.println("\n");
    }
    public void insertion()
    {
        System.out.print("(insertionsort)\n\n");
        display();
        for(int j=2;j<=n;j++)
        {
            int key=a[j];int i=j-1;
            while((i>0)&&(a[i]>key))
            {
                a[i+1]=a[i];
                i--;
            }
            a[i+1]=key;
        display();
        }
    }
   
}

class insertionsort
{
    public static void main(String arg[]) throws IOException
    {
        DataInputStream x1= new DataInputStream(System.in);
       
        System.out.print("\nEnter the number of elements:");
        int na=Integer.parseInt(x1.readLine());
        arraylist ob=new arraylist(na+1);
        System.out.println("Enter the elements:");
        for (int k=1;k<=na;k++)
                ob.insert(Integer.parseInt(x1.readLine()));
       
        System.out.println("Before sorting:\n");
        ob.display();
        System.out.println("Sorting.............");
       
        ob.insertion();
        System.out.println("After sorting:\n");
        ob.display();
    }
}

Output:
nn@linuxmint ~ $ javac insertionsort.java
Note: insertionsort.java uses or overrides a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
nn@linuxmint ~ $ java insertionsort

Enter the number of elements:5
Enter the elements:
5
4
3
2
1
Before sorting:

5 4 3 2 1

Sorting.............
(insertionsort)

5 4 3 2 1

4 5 3 2 1

3 4 5 2 1

2 3 4 5 1

1 2 3 4 5

After sorting:

1 2 3 4 5

nn@linuxmint ~ $