Thread: Arraylist indexof problem

mainData.java

public class mainData{
    public animalsData animal = new animalsData();
    public static void main(String[] args) {
    	mainData mn = new mainData();
    	mn.newAnimal();
    }
    public void newAnimal(){
    	animal.create("CAT", "4");
    	animal.create("DOG", "5");
    	System.out.println(animal.animalIndex("DOG"));
    }
}

animalsData.java

public class animalsData{
    String name, l;
    ArrayList<animalsData> animals = new ArrayList<animalsData>();
    public animalsData(){}//def constructor
    public animalsData(String name, String l){
    	super();
    	this.name= name;
    	this.l= l;
    }
    public void create(String name, String l){
    	animals.add(new animalsData(name, l));
    }
    public int animalIndex(String name){
    	return this.animals.indexOf(name);
    }
}

create method working normally and add object to list, but when i call animalIndex method i given this problem;
**return only -1 why?**