Tutorial Playlist
191 Lessons1. Introduction to Java
2. What is Java?
3. History of Java
4. Java Tutorial for Beginners
5. How Do Java Programs Work?
6. JDK in Java
7. C++ Vs Java
8. Java vs. Python
9. Java vs. JavaScript
10. From Java Source Code to Executable
11. How to Install Java in Linux
12. How to Install Java in Windows 10
13. Java Hello World Program
14. Structure of Java Program and Java Syntax
15. Operators in Java
16. Java If-else
17. Switch Case In Java
18. Loops in Java
19. Infinite loop in Java
20. For Loop in Java
21. For Each Loop in Java
22. Constructor in Java
23. Constructor Overloading in Java
24. Copy Constructor in Java
25. Default Constructor in Java
26. Parameterized Constructors in Java
27. Constructor Chaining In Java
28. Finalize Method in Java
29. Static Method in Java
30. Equals Method in Java
31. Abstract Method in Java
32. toString() Method in Java
33. Difference between equals method in Java
34. Inheritance in Java
35. Multiple Inheritance in Java
36. Hierarchical Inheritance in Java
37. Java Classes and Objects
38. Scanner Class in java
39. All classes in java are inherited from which class
40. What is Nested Class in Java
41. POJO Class in Java
42. Anonymous Class in Java
43. Final Class in Java
44. Object Class in Java
45. Packages in Java
46. Access Modifiers in Java
47. Static Keyword In Java
48. Final Keyword in Java
49. Checked and Unchecked Exceptions in Java
50. User Defined Exception in Java
51. Error vs. Exception in Java
52. Java Collection
53. Collections in Java
54. Garbage Collection in Java
55. Generics In Java
56. Java Interfaces
57. Functional Interface in Java
58. Marker Interface in Java
59. Streams in Java
60. Byte stream in java
61. File Handling in Java
62. Thread in Java
63. Thread Lifecycle In Java
64. Daemon Thread in Java
65. Thread Priority in Java
66. Deadlock in Java
67. String Pool in Java
68. Java Database Connectivity(JDBC)
69. Design Patterns in Java
70. Functional Programming in Java
71. OOP vs Functional vs Procedural
72. Heap Memory and Stack Memory in Java
73. Applet in Java
74. Java Swing
75. Java Frameworks
76. Hibernate Framework
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77. JUnit Testing
78. How to Install Eclipse IDE for Java?
79. Command line arguments in Java
80. Jar file in Java
81. Java Clean Code
82. OOPs Concepts in Java
83. Java OOPs Concepts
84. Overloading vs Overriding in Java
85. Java 8 features
86. String in Java
87. String to int in Java
88. Why String Is Immutable in Java?
89. Primitive Data Types in Java
90. Non-Primitive Data Types in Java
91. This and Super Keyword in Java
92. HashMap in Java
93. Comparable And Comparator in Java
94. Type Casting in Java
95. Arrays Sort in Java with Examples
96. Variable Hiding and Variable Shadowing in Java
97. Enum in Java
98. Substring in Java
99. Pattern Programs in Java
100. Hashcode in Java
101. What is ByteCode in Java?
102. How To Take Input From User in Java
103. GCD of Two Numbers in Java
104. Linked List in Java
105. Arithmetic Operators in Java
106. Conditional Operators in Java
107. Stack and Queue in Java
108. Array Length in Java
109. Number Pattern Program in Java
110. Split in java
111. Map In Java
112. Difference Between Throw and Throws in Java
113. Difference Between Data Hiding and Abstraction
114. HashSet in Java
115. String Length in Java
116. Factorial Using Recursion in Java
117. DateFormat in Java
118. StringBuilder Class in java
119. Instance variables in Java
120. Java List Size
121. Java APIs
122. Reverse an Array in Java
123. StringBuffer and StringBuilder Difference in Java
124. Java Program to Add Two Numbers
125. String to Array in Java
126. Regular Expressions in Java
127. Identifiers in Java
128. Data Structures in Java
129. Set in Java
130. Pass By Value and Call By Reference in Java
131. Try Catch in Java
132. Bubble Sort in Java
133. Caesar Cipher Program in Java
134. Queue in Java
135. Object Creation in Java
136. Multidimensional Array in Java
137. How to Read a File in Java
138. String Comparison in Java
139. Volatile Keyword in Java
140. Control Statements in Java
141. Jagged Array in Java
142. Two-Dimensional Array in Java
143. Java String Format
144. Replace in Java
145. charAt() in Java
146. CompareTo in Java
147. Matrix Multiplication in Java
148. Static Variable in Java
149. Event Handling in Java
150. parseInt in Java
151. Java ArrayList forEach
152. Abstraction in Java
153. String Input in Java
154. Logical Operators in Java
155. instanceof in Java
156. Math Floor in Java
157. Selection Sort Java
158. int to char in Java
159. Stringtokenizer in java
160. Implementing and Manipulating Abs in Java
161. Char array to string in java
162. Convert Double To String In Java
163. Deque in Java
164. Converting a List to an Array in Java
165. The Max function in java
166. Removing whitespace from string in java
167. String arrays in Java
168. Strings in Java Vs Strings in Cpp
169. Sum of digits of a number in Java
170. Art of Graphical User Interfaces
171. Trim in Java
172. RxJava
173. Recursion in Java
174. HashSet Java
175. Difference Between Java and Python
176. Square Root in Java
177. Reverse A String in Java
178. Even Odd Program in Java
179. Fibonacci Series in Java
180. Prime Number Program in Java
181. Java Program to Print Prime Numbers in a Given Range
182. Java Leap Year Program
183. Swapping of Two Numbers in Java
184. LCM of Two Numbers in Java
185. Math.sqrt() Function in Java
186. Area of Triangle in Java
187. Sort a String In Java
188. Factorial Program in Java
189. Javafx
190. Lambda expression in java
191. Setup Java Home and IDE on macOS
In the world of Java development, Hibernate is a powerful and popular framework for Object-Relational Mapping (ORM). It simplifies the process of interacting with relational databases by providing an intuitive and efficient way to map Java objects to database tables.
In this blog post, we will explore the fundamentals of Hibernate in Java, discussing its features, advantages, and practical examples to demonstrate its capabilities.
Hibernate is a popular ORM tool that allows developers to work with databases using object-oriented concepts instead of dealing with complex SQL queries. It bridges the object-oriented world of Java and the relational world of databases, providing seamless integration and simplifying data persistence.
To illustrate the usage of Hibernate, let's consider a real-life example of a web application that manages employee information.
We will create a Java class called "Employee" and annotate it with Hibernate annotations, such as @Entity, @Table, and @Column, to map it to a corresponding database table. We can then perform CRUD operations on the Employee objects using Hibernate's session management and transaction support.
To start our Hibernate tutorial, let's dive into a practical example demonstrating how to use Hibernate to manage employee information in a web application. We will create a Java class called "Employee" and leverage Hibernate annotations to map it to a database table.
First, we need to set up the Hibernate configuration file, usually named "hibernate.cfg.xml." This file contains database connection details, such as the JDBC driver, URL, username, and password. It also defines other Hibernate-specific settings.
Here's an example of a basic Hibernate configuration file:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<!-- Database connection settings -->
<property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="hibernate.connection.url">jdbc:mysql://localhost:3306/employee_db</property>
<property name="hibernate.connection.username">your_username</property>
<property name="hibernate.connection.password">your_password</property>
<!-- Hibernate specific settings -->
<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
<!-- Mapping resources -->
<mapping class="com.example.Employee" />
</session-factory>
</hibernate-configuration>
Make sure to replace "your_username" and "your_password" with your actual database credentials. Also, modify the JDBC driver class and database URL as per your database setup.
Now, let's create the Java class "Employee" which will be mapped to a corresponding database table. The class should include appropriate Hibernate annotations to define the table and its columns.
Here's an example:
import javax.persistence.*;
@Entity
@Table(name = "employees")
public class Employee {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "id")
private Long id;
@Column(name = "name")
private String name;
@Column(name = "position")
private String position;
// Getters and Setters
// ...
}
In this example, we have annotated the class with @Entity to indicate that it is a persistent entity.
The @Table annotation specifies the name of the corresponding database table. The @Id annotation denotes the primary key, and @GeneratedValue indicates that the ID value will be generated automatically. Each class variable is annotated with @Column, specifying the corresponding column name in the table.
With the Hibernate configuration and the Employee class in place, we can now perform CRUD operations on the Employee objects. Hibernate provides a Session object to manage these operations. Let's take a look at some example operations:
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
public class EmployeeDAO {
private static SessionFactory sessionFactory;
public static void main(String[] args) {
// Set up Hibernate session factory
Configuration configuration = new Configuration();
configuration.configure("hibernate.cfg.xml");
sessionFactory = configuration.buildSessionFactory();
// Create a new employee
createEmployee("John Doe", "Manager");
// Retrieve an employee by ID
Employee employee = getEmployeeById(1L);
System.out.println("Retrieved employee: " + employee.getName() + " - " + employee.getPosition());
// Update an employee
employee.setPosition("Senior Manager");
updateEmployee(employee);
// Delete an employee
deleteEmployee(employee);
}
public static void createEmployee(String name, String position) {
Session session = sessionFactory.openSession();
Transaction transaction = session.beginTransaction();
Employee employee = new Employee();
employee.setName(name);
employee.setPosition(position);
session.save(employee);
transaction.commit();
session.close();
}
public static Employee getEmployeeById(Long id) {
Session session = sessionFactory.openSession();
Employee employee = session.get(Employee.class, id);
session.close();
return employee;
}
public static void updateEmployee(Employee employee) {
Session session = sessionFactory.openSession();
Transaction transaction = session.beginTransaction();
session.update(employee);
transaction.commit();
session.close();
}
public static void deleteEmployee(Employee employee) {
Session session = sessionFactory.openSession();
Transaction transaction = session.beginTransaction();
session.delete(employee);
transaction.commit();
session.close();
}
}
In this example, we first set up the Hibernate session factory using the configuration file we created earlier. Then, we perform CRUD operations by opening a session, beginning a transaction, and executing the desired operations, such as saving, retrieving, updating, and deleting employee objects.
ORM, which stands for Object-Relational Mapping, is a crucial concept in modern software development. As a result, developers can bridge the gap between object-oriented programming languages like Java and relational databases.
The Hibernate ORM tool plays a vital role in simplifying the process of mapping Java objects to database tables and managing the interaction between the two.
ORM tools like Hibernate provide a layer of abstraction that allows developers to work with objects and classes instead of dealing directly with SQL queries and database tables. By leveraging Hibernate's capabilities, developers can focus more on their application's business logic rather than getting caught up in the complexities of database interactions.
Let's take a closer look at how Hibernate ORM helps in managing the interaction between objects and relational databases:
1. Mapping Java Classes to Database Tables
Hibernate uses annotations or XML configuration to map Java classes to corresponding database tables. By providing annotations like @Entity, @Table, and @Column, developers can specify the mapping details, such as the table name, column names, and data types. This mapping enables Hibernate to understand how to store and retrieve object data from the database.
2. Object Persistence
Hibernate simplifies the process of persisting objects in the database. When an object is created or modified, Hibernate automatically generates the necessary SQL statements to insert or update the corresponding database table. Developers don't need to write manual SQL queries or worry about low-level database operations. Hibernate takes care of these tasks, allowing developers to focus on their application's logic.
3. Retrieving Objects from the Database
With Hibernate ORM, developers can retrieve objects from the database using various querying techniques. Hibernate provides its own query language called Hibernate Query Language (HQL), which is similar to SQL but operates on objects instead of database tables. Also, developers can use HQL to perform complex queries, filtering, sorting, and aggregations. Additionally, Hibernate supports criteria and native SQL queries for more advanced scenarios.
4. Lazy Loading and Caching
Hibernate ORM incorporates features like lazy loading and caching to optimize performance. Lazy loading enables Hibernate to load associated objects or collections only when they are accessed, reducing unnecessary database queries and improving efficiency. Conversely, caching allows Hibernate to store frequently accessed data in memory, reducing the need for repetitive database retrievals and enhancing overall application performance.
5. Transaction Management
Hibernate in Java provides transaction management capabilities, ensuring data consistency and integrity. Developers can use its transaction support to define and manage transactions, enabling them to group multiple database operations into atomic units. Transactions help maintain data integrity by ensuring that all operations within a transaction are successful or none are committed.
Overall, Hibernate, as an ORM tool, simplifies and streamlines the process of working with relational databases in Java applications. It allows developers to focus on their application's business logic by abstracting away the complexities of SQL queries and database interactions. It also provides a higher level of abstraction, improves productivity, and enhances the maintainability of codebases. Therefore, Hibernate's ORM capabilities make it an invaluable tool for building robust and scalable Java applications that interact with relational databases.
Hibernate is often used in conjunction with the Java Persistence API (JPA), which is a standard specification for ORM in Java. JPA defines a set of annotations and APIs that Hibernate implements, making switching between different ORM frameworks easier while maintaining code compatibility. JPA provides a consistent programming model for ORM in Java applications, allowing developers to write portable and vendor-independent code.
Hibernate framework offers several advantages, making it a preferred choice for Hibernate ORM in Java applications. They include:
The need for Hibernate framework arises from the complexities involved in manually writing SQL queries and handling database interactions. By using Hibernate, developers can focus on business logic rather than dealing with low-level database operations.
Hibernate framework handles tasks such as connection management, transaction handling, and mapping objects to database tables, streamlining the development process and reducing the time and effort required to build robust and scalable applications.
Hibernate is an open-source framework that was initially developed by Gavin King and later acquired by Red Hat. It has a large and active community of developers who contribute to its ongoing development and support. Hibernate follows the principles of Object-Relational Mapping, making it easier for Java developers to work with databases and enabling faster application development.
Hibernate provides a wide range of functionalities to simplify database operations in Java applications. Some of the key functionalities include:
Hibernate is a robust, feature-rich framework that simplifies object-relational mapping in Java applications. By leveraging Hibernate's capabilities, developers can focus on business logic while letting the framework handle database interactions. Its caching mechanisms, transaction management, and support for various databases empower developers to build scalable and efficient applications. By exploring Hibernate and understanding its advantages, you can enhance your Java development skills and take your projects to the next level.
1. How does Hibernate simplify database operations?
Answer: Hibernate simplifies database operations by abstracting complex SQL queries. Using its intuitive API, developers can work with objects and classes, allowing the framework to generate the necessary SQL queries based on object mappings. This eliminates the need for developers to write low-level database access code and reduces the complexity of interacting with databases.
2. How does Hibernate optimize performance?
Answer: Hibernate optimizes performance through caching and lazy loading techniques. Caching allows frequently accessed data to be stored in memory, reducing the need for repetitive database queries and improving response times.
3. How does Hibernate ensure database portability?
Hibernate ensures database portability by abstracting the underlying database-specific details. Developers can write database-independent code as it handles the differences in SQL dialects and database-specific features. This allows applications to be easily switched between different database vendors without requiring modifications to the application code, providing flexibility and reducing vendor lock-in.
4. How does Hibernate promote code reusability and maintainability?
Hibernate promotes code reusability and maintainability by encapsulating database access logic within its API. Developers can create reusable data access codes that can be shared across multiple applications or modules.
PAVAN VADAPALLI
Director of Engineering
Director of Engineering @ upGrad. Motivated to leverage technology to solve problems. Seasoned leader for startups and fast moving orgs. Working …Read More
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upGrad does not grant credit; credits are granted, accepted or transferred at the sole discretion of the relevant educational institution offering the diploma or degree. We advise you to enquire further regarding the suitability of this program for your academic, professional requirements and job prospects before enr...