Insertion in B-Tree in Java

class BTree
{   
    private int T;  

    public class Node
    {          
        int n;
        int key[] = new int[2 * T - 1];
        Node child[] = new Node[2 * T];
        boolean leaf = true;
 
        public int Find (int k)
        {                        
            for (int i = 0; i < this.n; i++)
	        {	             
                if (this.key[i] == k)
	            {            
                    return i;
                }	        
            }                        
            return -1;
        };       
    }
 
    public BTree(int t)
    {             
        T = t;
        root = new Node ();
        root.n = 0;
        root.leaf = true;
    } 

    private Node root;
     
    // split
    private void split (Node x, int pos, Node y)
    {             
        Node z = new Node ();
        z.leaf = y.leaf;
        z.n = T - 1;

        for (int j = 0; j < T - 1; j++)
        {	        
            z.key[j] = y.key[j + T];
        } 
        if (!y.leaf)
        {	        
            for (int j = 0; j < T; j++)
	        {	            
                z.child[j] = y.child[j + T];
            } 
        }          
        y.n = T - 1;
    
        for (int j = x.n; j >= pos + 1; j--)
        {	        
            x.child[j + 1] = x.child[j];
        } 
        x.child[pos + 1] = z;   

        for (int j = x.n - 1; j >= pos; j--)
        {	        
            x.key[j + 1] = x.key[j];
        } 
        x.key[pos] = y.key[T - 1];
        x.n = x.n + 1;
    } 
 
     // insert key
    public void insert (final int key)
    {             
        Node r = root;

        if (r.n == 2 * T - 1)
        {	    
            Node s = new Node ();
            root = s;
            s.leaf = false;
            s.n = 0;
            s.child[0] = r;
            split (s, 0, r);
            _insert (s, key);
        }
        else
        {	        
            _insert (r, key);
        }       
    } 
    // insert node
    final private void _insert (Node x, int k)
    {    
 
        if (x.leaf)
        {	        
            int i = 0;
	
	        for (i = x.n - 1; i >= 0 && k < x.key[i]; i--)
	        {	            
                x.key[i + 1] = x.key[i];
            }	    
            x.key[i + 1] = k;
            x.n = x.n + 1;
        }
        else
        {	    
            int i = 0;

            for (i = x.n - 1; i >= 0 && k < x.key[i]; i--)
	        {	      
            };
            i++;
            
            Node tmp = x.child[i];
            if (tmp.n == 2 * T - 1)
	        {
                split (x, i, tmp);
                if (k > x.key[i])
	            {	        	
                    i++;
                }	      
            }	    
            _insert (x.child[i], k);
        }   
    }   
    
    public void display ()
    {
        display (root);
    }  

    // Display the tree
    private void display (Node x)
    {      
        assert (x == null);
        for (int i = 0; i < x.n; i++)
        {	    
            System.out.print (x.key[i] + " ");
        } 
        
        if (!x.leaf)
        {	
            for (int i = 0; i < x.n + 1; i++)
	        {	    
                display (x.child[i]);
            } 
        }   
    } 
}
public class Main{
    public static void main (String[]args)
    {         
        BTree b = new BTree(1);
        b.insert(5);
        b.insert (6);
        b.insert (7);
        b.insert (8);
        b.insert (12);
        b.insert (13);
        b.insert (14);
        b.display ();
    } 
}