java程序怎么运行

//MainApp.java 

public class MainApp { 

    public static void main(String[] args) { 

        Animal animal = new Animal("Puppy"); 

        animal.printName(); 

    } 

} 

//Animal.java 

public class Animal { 

    public String name; 

    public Animal(String name) { 

        this.name = name; 

    } 

    public void printName() { 

        System.out.println("Animal ["+name+"]"); 

    } 

}