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Data Software Design Pitfalls on Java: Should We Have a Constructor on JPA?

The data in any modern and distributed architecture, such as microservices, work as a vein in a system. It fits like a state in a stateless application. On the other hand, we have the most popular paradigms in the code, especially when we talk about enterprise OOP. How do you combine both archive and software design, primarily on Java? 

This article will explore more details on code, especially inside the Jakarta EE world, mainly to answer the questions in a previous Jakarta JPA discussion: should we have a constructor on JPA, and why?

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Inheritance vs. Composition in JPA

Introduction

«Don't repeat yourself» or «DRY». Developers try to adhere to this principle during software development. It helps to avoid redundant code writing and, as a result, simplifies its maintainability in the future. But how to achieve this principle in the JPA world?

There are two approaches: Inheritance and Composition. Both have their pros and cons. Let's figure out what they are on the not quite "real-world" but representative example.

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How JPAstreamer Can Help You Write Type-Safe Hibernate Code Without Unnecessary Complexity

For the past 10 or so years, JPA has been one of the most popular ways of accessing a database within the Java ecosystem. Even if you haven't heard of JPA directly, there is a high likelihood that you've heard of or even used one of the most popular implementations of the JPA API - Hibernate.

The reason why JPA is so popular is no secret - most of the inconveniences are abstracted from the user, making the API very intuitive to use. Let's say that in some random database exists a table called person with the following structure:

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Deploy Quarkus Faster in The Cloud with Platform.sh. Part 2: PostgreSQL with JPA

Quarkus is, in its own words, a cloud-native, (Linux) container-first framework for writing Java applications. It has become popular lately because of the amazingly fast boot time, incredibly low RSS memory. In this series of articles about Quarkus, we'll discuss how to deploy a Quarkus application even faster to the cloud with Platform.sh.

The first step is to create the application itself, and Quarkus has proper documentation. You have either a Maven Archetype or the start code link where you can define the dependencies that you need to write your application.

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Getting Started With Jakarta EE and Eclipse MicroProfile

Never heard of Jakarta EE and Eclipse MicroProfile yet? Then it's time to give it the first try and see how the Java Enterprise standard evolved. By developing a small application, this post demonstrates how to use these two technologies to build cloud-ready and state-of-the-art enterprise applications.

What Is Jakarta EE?

In a nutshell, it's a set of specifications (JAX-RS, CDI, JPA, JSON-P, etc.) to write enterprise applications with Java. These specifications are documents defining the API and interaction of a technology.

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Hibernate Envers: Simple Implementations (Part 1)

Introduction

Auditing is an important part of software applications. Almost every business domain requires an audit log to manage the changes of acquired data. More than that, auditing is also required to keep applications safe from fraudulent and unethical access. Many applications also check the changelog of data for their internal processes. Many Java-based software implement triggers on the database layer for auditing, but Hibernate gives a more convenient way to implement auditing.

Hibernate Envers: Features

Hibernate Envers is a framework for auditing. Though Hibernate is an ORM technology, auditing tasks based on Hibernate entities means changes on the entity is audited and saved on the database. Auditing of all mappings is defined by the JPA specification. Revision of each entity log is saved by Hibernate Envers. Hibernate Envers gives the way to read historical data log. 

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Optimizing Relationships Between Entities in Hibernate

In this post, following the example project that you have here, I am going to explain how to optimize queries to a database using JPA.

You will see different types of queries explaining how to make connections between lazy and eager tables. The tables will be joined by a single field, by several and even by one, but adding a static condition.

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How to Enrich DTOs With Virtual Properties Via Spring Projections

In JPA, as a rule of thumb, our queries (SQLs) must extract from the database only the needed data, meaning only the data that it is prone to be modified. When the fetched data is read-only (we don't plan to modify it), then we must strive to fetch it as DTOs instead of JPA entities. 

Starting from this statement, let's consider the following JPA trivial entity:

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Kotlin Microservices With Micronaut, Spring Cloud, and JPA

The Micronaut Framework provides support for Kotlin built upon the Kapt compiler plugin. It also implements the most popular cloud-native patterns, like distributed configuration, service discovery, and client-side load balancing. These features allow you to include an application that's been built on top of Micronaut into an existing microservices-based system. The most popular example of such an approach may be integration with the Spring Cloud ecosystem. If you have already used Spring Cloud, it is very likely you built your microservices-based architecture using the Eureka discovery server and Spring Cloud Config as a configuration server. Beginning with version 1.1, Micronaut supports both these popular tools as part of the Spring Cloud project. That's good news because, in version 1.0, the only supported distributed solution was Consul, and there was no way to use Eureka discovery together with Consul's property source (running them together ends with an exception).

In this article, you will learn how to: