JDBC and APIs are the backbone of Java backend connectivity — enabling seamless communication between Java applications, databases, and external services.
JDBC (Java Database Connectivity) is an API that enables Java applications to connect with relational databases such as MySQL, Oracle, and PostgreSQL. It allows developers to send SQL queries directly from Java code and process results dynamically.
Connect Java applications to databases and perform CRUD operations. Example: In an online gas booking system, JDBC is used to store booking details in a MySQL database.
JDBC is part of the standard Java library, making it easy to use with any relational database. Example: A single JDBC interface can switch between MySQL and Oracle by just changing the driver.
Requires specific JDBC drivers and verbose coding for large applications. Example: Manually closing ResultSet, Statement, and Connection objects can be tedious in big projects.
DriverManager.ResultSet.
// Simple JDBC Example
import java.sql.*;
class Demo {
public static void main(String args[]) {
try {
Class.forName("com.mysql.cj.jdbc.Driver");
Connection con = DriverManager.getConnection(
"jdbc:mysql://localhost:3306/testdb", "root", "password");
Statement stmt = con.createStatement();
ResultSet rs = stmt.executeQuery("SELECT * FROM users");
while(rs.next())
System.out.println(rs.getString(1) + " " + rs.getString(2));
con.close();
} catch(Exception e) {
System.out.println(e);
}
}
}
Always close database connections, use PreparedStatement to prevent SQL injection, handle exceptions gracefully, and use connection pooling for performance.
Example: Using HikariCP for JDBC connection pooling in enterprise systems.
API (Application Programming Interface) provides a set of rules and methods for software components to interact. In Java, APIs are used to communicate between applications or systems, typically through REST or SOAP protocols.
Enable communication between systems using standardized methods. Example: A Java REST API can send customer data from a website to a mobile app.
APIs promote modular development and simplify integration with other technologies. Example: A payment gateway API helps connect your Java app with Paytm or Razorpay.
Security challenges, version mismatches, and dependency on network reliability. Example: A REST API call may fail if the internet connection is unstable.
// Simple REST API Example
@RestController
@RequestMapping("/api")
public class UserController {
@GetMapping("/user")
public String getUser() {
return "Welcome to Bhau Automation Java API!";
}
}
Follow RESTful standards, use authentication like JWT or OAuth, handle errors with proper response codes, and test endpoints using tools like Postman or Swagger. Example: A secured API returning JSON response — {"status":"success","message":"User created"}