如何从另一个类添加元素到jList？

I am using netbeans 6.9.1. I have a jframe, and the jframe has a jList and the DefaultListModel name is lm. I would like to add elements to this jList using another class, but i can't figure out how, and can't find anything on it online...I guess i have to find a way to get the DefaultListmodel into my class also...? 6.9.1. I have a jframe, and