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Exception in thread "main" java.lang.NullPointerException



Asked on March 11, 2015
Wanna print the name of author and the title of the book.
BooksTestDrive.java
public class Books {
String title;
String author;
}

class BooksTestDrive{
public static void main(String[] args) {
Books[] myBooks = new Books[3];
int x = 0;
myBooks[0].title = "The Grapes of Java";
myBooks[1].title = "The Java Gatsby";
myBooks[2].title = "The Java CookBook";
myBooks[0].author = "bob";
myBooks[1].author = "sue";
myBooks[2].author = "ian";
while(x < 3){
System.out.print(myBooks[x].title);
System.out.print(" by ");
System.out.println(myBooks[x].author);
x = x + 1;
}
}



Replied on March 11, 2015
You have to actually make the Books objects !


Replied on March 11, 2015
Create the  Books objects like..

myBooks[0] = new Books();
myBooks[1] = new Books();
myBooks[2] = new Books();

BooksTestDrive.java

public class Books {
String title;
String auther;
}

class BooksTestDrive{
public static void main(String[] args) {
Books[] myBooks = new Books[3];
int x = 0;
// Books object
myBooks[0] = new Books();
myBooks[1] = new Books();
myBooks[2] = new Books();
myBooks[0].title = "The Grapes of Java";
myBooks[1].title = "The Java Gatsby";
myBooks[2].title = "The Java CookBook";
myBooks[0].auther = "bob";
myBooks[1].auther = "sue";
myBooks[2].auther = "ian";
while(x < 3){
System.out.print(myBooks[x].title);
System.out.print(" by ");
System.out.println(myBooks[x].auther);
x = x + 1;
}
}
}



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