First Import library.sql to MYSQL database from the folder "Java library management system" and Change the database connection parameters from the source code based on your driver and server information
#For example, from your source code you need to modify the parameter of the following two lines:
Class.forName("com.mysql.jdbc.Driver");
con=DriverManager.getConnection("jdbc:mysql://localhost:3306/librar","root","root");
#Then Import the project to NetBeans IDE
#done