Top 5 Hibernate Books for Java Developers - Best, Must read

Hibernate is one of the most popular, open-source ORM (Object Relational Mapping) framework, which has now become a standard for developing persistence layer on Java enterprise application, along with JPA (Java Persistence API). I often receive requests to suggest which book is best to learn to hibernate or recommendation about some good books and training courses on Spring and Hibernate. This motivates me to write this article about some of the best books on Hibernate currently available on the market.

10 Examples of ConcurrentHashMap in Java

Hello guys, if you are new to Java programming and want to learn ConcurrentHashMap class in Java then you have come to the right place. Earlier, I have shared the best books and best courses to learn Java, and today, I am going to share 10 examples of using ConcurrentHashMap in Java. As a Java programmer, you might have heard about the ConcurrentHashMap class of java.util.concurrent package. If you don't let me tell you that ConcurrentHashMap is an important class in Java and you will often find yourself dealing with this class in a multithreaded and concurrent Java application. If you are wondering where to start and how to master this essential Java class then you have come to the right place.

How to setup JNDI Database Connection pool in Tomcat - Spring Tutorial Example

Setting the JNDI Database Connection pool in Spring and Tomcat is pretty easy. Tomcat server documentation gives enough information on how to set up a connection pool in Tomcat 5, 6, 7, 8, or 9. Here we will use Tomcat 7 along with the spring framework for creating a connection pool in the Tomcat server and accessing them in Spring using JNDI code. In our last article, we have seen how to set up a database connection pool in Spring for a core Java application that doesn't run on a web server or application server and doesn't have a managed Java EE container.

Why use Cloud Computing? Advantages and Disadvantages

Hello guys, If you are curious about what is Cloud computing and why every company both big and small are going to cloud native then you have come to the right place. In the past, I have shared best Cloud Computing courses and both free and paid courses to learn popular cloud platforms like AWS, GCP, and Azure. In this article, I am going back to basics and tell you about what is cloud computing and what benefits it offer. Cloud Computing has been a buzz word in the IT world from the last few years. When it first appeared, like many things, a lot of people has dismissed it as being the next big thing, but cloud computing has certainly lived up to expectation and truly shift how the Information technology arm of business function today.

SQL Self Join Example - SQL Query to Find Employees Earning More Than Managers - LeetCode Solution

Hello guys, are you looking for a simple example to understand how to use SELF JOIN in SQL? If yes, then you have come to the right place. In this article, I'll show you how you can use Self join to solve interesting SQL problems from LeetCode. Along the way, you will also learn this useful SQL concept. So, what are you waiting for, let's first check the problem, and then we'll write an SQL query using SELF Join to solve this problem.

Write an SQL Query to Find Employees Earning More Than Managers
The Employee table holds all employees including their managers. Every employee has an Id, and there is also a column for the manager Id as shown below:

+----+-------+--------+-----------+
| Id | Name  | Salary | ManagerId |
+----+-------+--------+-----------+
| 1  | Joe   | 70000  | 3         |
| 2  | Henry | 80000  | 4         |
| 3  | Sam   | 60000  | NULL      |
| 4  | Max   | 90000  | NULL      |
+----+-------+--------+-----------+

Given the Employee table, write a SQL query that finds out employees who earn more than their managers. For the above table, Joe is the only employee who earns more than his manager because Henry's Manager is Max who earns 90000 which is more than Henry's salary of 80000.

Difference between row_number(), rank() and dense_rank() window functions in SQL

Though all three are ranking functions in SQL, also known as a window function in Microsoft SQL Server, the difference between rank(), dense_rank(), and row_number() comes when you have ties on ranking i.e. duplicate records. For example, if you are ranking employees by their salaries then what would be the rank of two employees of the same salaries? It depends on which ranking function you are using like row_number, rank, or dense_rank.