Save vs. saveOrUpdate vs. persist in Hibernate
What is the difference between save and saveOrUpdate or Difference between saving and persist are common interview question in any Hibernate interview, much like the difference between get and load method in Hibernate. Hibernate Session class provides a couple of ways to save an object into the database by methods like save, saveOrUpdate, and persist. You can use either save(), saveOrUpdate() or persist() based upon your requirement for persisting objects into the database. The key thing is that all these objects are used to store data into the database but they also make a transient object persistent in Hibernate.
Hello All, today, I am going to share some useful tips to prepare for Oracle's Java certifications like OCAJP and OCPJP, both associate and programmer level certification. These certifications are great for both mastering Java language as well as getting recognition for your skill which not only improves your chances of getting a Java development job but also helps you in your career growth. Though you need a bit of Java experience or knowledge to pass the Exam. If you are entirely new to Java, then you need to first go through a comprehensive course like The Complete Java MasterClass on Udemy and learn how to program in Java, because getting certified without knowing how to program in Java is of no use.
The OOP or Object Oriented Programming is one of the most popular programming paradigms which helps you to organize code in the real-world system. It's a tool that allows you to write sophisticated software by thinking in terms of objects and relationships. Unlike its predecessor procedural Programming paradigm, which is implemented most notably by C, which solves the problem and complete task by writing code for computers, the OOP style of programming allows you to think in terms of real-world objects which have both state and behavior. You can view anything as objects and then find their state and behaviors, this will help you to simulate that object in code.
You might be thinking, why should a Java developer read a book on Performance tuning? When I first faced this question a long time back, I thought I will do it later, but I never got back to that for a long time. I realize my mistake of having a lack of knowledge on memory measurement, JVM tuning, and finding bottleneck only when I faced severe performance and scalability issues on our mission-critical, server-side financial application written in Java. It's true that when you really need it, you learn most, but those times are not the best time to learn fundamentals, in fact, those times are to apply and correct your misunderstanding.
I often receive a request from my readers and fellow Java developers about book recommendations to learn Servlet and JSP, two of the key web technology for server-side web development in Java. Unfortunately, there are not many good books to learn Servlet and JSP for Java web developers. Despite being the most popular Java Web technology, there are very few good books to learn Servlet and JSP. The one book which everybody will suggest to you is the Head First Servlet and JSP, which is indeed one of the best books but it's outdated now. It doesn't cover the latest development in Servlet API, particularly Servlet 3.0, and also not been updated for the last 7 to 8 years, but considering others, it is still an excellent book to learn Servlet and JSP.
Data Structure and Algorithms books are often taught as textbooks in various universities, colleges, and Computer Science degree courses, yet, when you put programmers in a situation, where they need to find and decide, which data structures and algorithms to use to solve a problem, they struggle. I have seen this, and I think one reason for this is perspective. When you read something like a textbook and your perspective is just to do well in the exam, you might not be thinking about learning and applying that knowledge to real-world problems. Since data structures and algorithms are the core of any programming problem, it becomes extremely important for programmers to master them even if you have learned well during academics.
Scala is another JVM based programming language, which is quickly gaining popularity because of its exciting mix of object-oriented and functional programming paradigm. Many companies have started using Scala for there strategic and mission-critical development. One of the best known is Twitter, which is also one of the key factors in the growing popularity of the Scala programming language. If you are a Java, C++ or C# programmer, who is willing to learn Scala in your spare time, then you will be surprised to see how much helpful content is available for FREE on the internet. By the way, Java 8 is not far away, the only couple of months to go, and there are already some decent tutorials available online. If you are learning Java 8, you may like to see my list of resources on Java 8 as well.
Some of you might ask, Why software development project managers should read books? Isn't they are experienced enough to become a project manager and handle software development and manage Programmers? A genuine question, but Software management is harder than any other management purely because every Software or Project is different than the previous one. Many other streams of engineering, like Civil or Mechanical, got better in terms of estimation and management with the help of software, but software development is still run on experience.