编译器错误：需要数组，但找到字符串

Question

Getting a error: array required, but String found. I checked and rechecked, yet couldn't find anything wrong with my code. What's going wrong? I have been introduced to java a year ago, but only when i started working on a project to develop a library management system do I realise the serious deficiencies in my knowledge.

import java.util.Scanner;

public class library{
book[] bk = new book[5];

public static void main(String[] args){
    Scanner input = new Scanner(System.in);
    library mainObj = new library();

    mainObj.addBooks();
}

public void addBooks(){
    Scanner input = new Scanner(System.in);

    System.out.print("Book Name: ");
    String bk = input.nextLine();

    System.out.print("Author Name: ");
    String aun = input.nextLine();

    System.out.print("Id: ");
    String i = input.nextLine();

    bk[book.getTotalBookCount()] = new book(bk, aun, i);
}

}

class book{
String name;
String authorName;
String id;
static int totalBookCount = 0;

book(String bkn, String aun, String i){
    name = bkn;
    authorName = aun;
    id = i;
    totalBookCount++;

    System.out.println("Book Added!! ");
}

}

Answer 1

String bk = input.nextLine();

You're shadowing book[] bk with that variable. Either change the name of one of them, or use this instead.

this.bk[book.getTotalBookCount()] = new book(bk, aun, i);

Answer 2

You are using bk variable twice. Once at top while declaring array book[] bk = new book[5]; and once in addBooks function String bk = input.nextLine(); at third line.

Answer 3

You have used bk twice for two different types ie one for book array and another for string. And in these type of collisions, local type gets priority so,

 bk[.....] = ......;
 ^^^^^   
Here, `bk` will be considered as string, but we are using `[]` brackets with it, hence the error: array required, string found.