Basic Java-文本编辑器中的编码，尽管它们位于同一包中“无法找到符号”，但是无法从其他文件创建新对象

这段代码可以很好地编译：

人.java

package people;

class Person{
    private String name;
    private int age;

public Person(String name, int age){
    this.name = name;
    this.age = age;

}

public String getName(){
    return name;
}

public void setName(String name){
    this.name = name;
}

public int getAge(){
    return age;
}

public void setAge(int age){
    this.age = age;
}

}

这不是：

controller.java

package people;
public class controller{
    public static void main (String[] args){

        Person mark = new Person();
        mark.setName("Mark");
        mark.setAge(24);

    }
}

我收到此编译错误：

C:\Program Files\Java\jdk1.8.0_66\classes\controller.java:7: error: cannot find symbol
        Person mark = new Person();
        ^
  symbol:   class Person
  location: class controller
C:\Program Files\Java\jdk1.8.0_66\classes\controller.java:7: error: cannot find symbol
        Person mark = new Person();
                          ^
  symbol:   class Person
  location: class controller

我对此进行了很多研究，似乎无法弄清楚。我是否尝试在controller.java文件中错误地实例化该对象？谢谢。