Java에서 클래스 간의 관계는 무엇입니까?

/**
 * @Description: 依赖（Dependence)的定义：表示一个类依赖于另一个类的定义，一个类的方法操纵另一个类的对象
 * 应用于局域变量、方法的形参，或者对静态方法的调用。
 * @Author: 13394
 * @CreateDate: 2018/12/18 9:54
 */
public class Cook {
    public static void cook() {
        System.out.println("做饭");
    }

    public void eat() {
        System.out.println("吃饭");
    }

}
/**
 * @Description: TODO
 * @Author: 13394
 * @CreateDate: 2018/12/18 10:09
 */
public class BeforeCook {
    //局部变量
    public void before() {
        Cook cook = new Cook();
        System.out.println("饭前>>>>>>>>>>>>>>>");
        cook.eat();
    }

    //方法的形参
    public void before(Cook cook) {
        cook.eat();
    }

    //静态方法的调用
    public void before1() {
        Cook.cook();
    }

}

public class Cook {
    public static void cook() {
        System.out.println("做饭");
    }

    public void eat() {
        System.out.println("吃饭");
    }

}

    public class BeforeCook {
        //成员变量
       private Cook cook;
       public void setBefore(Cook cook){
           cook.eat();
       }

}

public class BeforeCook {
     //成员变量
    Cook cook;
    public BeforeCook(Cook cook){
        this.cook=cook;
    }
   }