Java class with a fucntion to determine the number of unique strings in an array of strings

Unique.java

public class Unique{

	public static void main(String [] args){
		Unique unique = new Unique();
		String[] _args = {"as", "as", "se", "so","so","an","no"};
		System.out.println(unique.det(_args));
	}
	

	public int det(String [] args_){
		int dup = 0;
		System.out.println(args_.length);
		for(int i = 0; i < args_.length; i++){
			for(int j = 0; j < args_.length; j++){
			 	if(i != j){
					if(args_[i].equals(args_[j])){
						dup +=1;
					}
				}

			} 
		}
		return args_.length - (dup);
	}


}