Write efficient code for extracting unique elements from a sorted list of array. e.g.

Write, efficient code for extracting unique elements from a sorted list of array. e.g.
 (1, 1, 3, 3, 3, 5, 5, 5, 9, 9, 9, 9) -> (1, 3, 5, 9).

public class Unique {
 public static void main(String args[])
  {
   int[] a=new int[]{1,1,1,3,3,3,4,4,4};
   int[] b=new int[10];
   
   int j=0;
   for(int i=0;i<a.length;i++)
   {
    if(!contains(b,a[i]))
    {
     b[j]=a[i];
     j++;
    }
    
    
   }
   
   for(int i=0;i<j;i++)
   {
    System.out.print(b[i]+" ");
   }
  }
  
  
  public static boolean contains(int a[],int data)
  {
        for(int i=0;i<a.length;i++)  
        {
      if(a[i]==data)   
         return true;
        }
        return false;
  }
  
 }