Cannot resolve method ‘println(void)‘ idea

package com.hsedu.list_;

import java.util.ArrayList;
import java.util.List;


public class ListExercise02 {
    public static void main(String[] args){
        List list = new ArrayList();
        list.add(new Book("红楼梦",33,"曹雪芹"));
        list.add(new Book("三国演义",24,"罗贯中"));
        list.add(new Book("水浒传",28,"吴承恩"));
        for (Object o :list) {
            System.out.println(o);
        }

        Book book = new Book("水浒传",28,"吴承恩");
        System.out.println(book.setBookName("西游记"));
        System.out.println(book.getBookName());

    }
}
//class Test{
//    Book.getBookName()
//}
class Book{
    private String bookName;
    private double price;
    private String author;

    public Book() {
    }

    public Book(String bookName, double price, String author) {
        this.bookName = bookName;
        this.price = price;
        this.author = author;
    }

    public String getBookName() {
        return bookName;
    }

    public void setBookName(String bookName) {
        this.bookName = bookName;
    }

    public double getPrice() {
        return price;
    }

    public void setPrice(double price) {
        this.price = price;
    }

    public String getAuthor() {
        return author;
    }

    public void setAuthor(String author) {
        this.author = author;
    }

    @Override
    public String toString() {
        return "Book{" +
                "bookName='" + bookName + ''' +
                ", price=" + price +
                ", author='" + author + ''' +
                '}';
    }
}

在下面这段代码中的中间一行提示报错Cannot resolve method 'println(void)'，运行后报错

D:idea_java_projectschapter14srccomhsedulist_ListExercise02.java:21:44
java: 此处不允许使用 '空' 类型

可能原因是println()方法没有这种用法，即当book对象在调用setBookName()方法后，再用println()方法去输出。把System.out.println()方法去掉即可不报错！直接book.setBookName("西游记");

Book book = new Book("水浒传",28,"吴承恩");
System.out.println(book.setBookName("西游记"));
System.out.println(book.getBookName());