问如何处理数组:线程“主”java.lang.ArrayIndexOutOfBoundsException: 3中的异常

EN

public class Sarray    
{    
        public static void main(String[] args)  
       {     



     Scanner scan = new Scanner(System.in); 
     System.out.print( "Enter sorted array length:" );
     int length = scan.nextInt();

     int[] a = new int[length];
     System.out.println("Enter integer sorted array:");      

     for(int i = 0;i<length;i++) 
     {
         String token = scan.next();
         a[i] = Integer.parseInt(token);         
     }       
     System.out.print("Unique array:");
     int[] b=new int[length];        
     int k=0;
     for(int i=0;i<length;i++)
     {  
        //here i got Exception              
         if(a[i] != a[i+1])
         {
             b[k++]= a[i];
         }
     }               
     for(int i=0;i<k;i++)
     {
         System.out.print(b[i]+" "); 
     }   
 }
}