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Mapping a Single Entity to Multiple Tables in JPA 1. Introduction JPA makes dealing with relational database models from our Java applications less painful. Things are simple when we map every table to a single entity class. But, sometimes we have reasons to model our entities and tables differently: When… Continue Reading jpa-mapping-single-entity-to-multiple-tables
The Java HashMap Under the Hood 1. Overview In this article, we are going to explore the most popular implementation of Map interface from the Java Collections Framework in more detail, picking up where our intro article left off. Before we get started with the implementation, it’s important to point… Continue Reading java-hashmap-advanced
Programmatic Transaction Management in Spring 1. Overview Spring’s @Transactional annotation provides a nice declarative API to mark transactional boundaries. Behind the scenes, an aspect takes care of creating and maintaining transactions as they are defined in each occurrence of the @Transactional annotation. This approach makes it easy to decouple our… Continue Reading spring-programmatic-transaction-management
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JPA Annotation for the PostgreSQL TEXT Type 1. Introduction In this quick tutorial, we’ll explain how to manage the PostgreSQL TEXT type using the annotations defined by the JPA specification. 2. The TEXT Type in PostgreSQL When working with PostgresSQL we may, periodically, need to store a string with an… Continue Reading jpa-annotation-postgresql-text-type
Java FileWriter 1. Overview In this tutorial, we’ll learn and understand the FileWriter class present in the java.io package. 2. FileWriter FileWriter is a specialized OutputStreamWriter for writing character files. It doesn’t expose any new operations but works with the operations inherited from the OutputStreamWriter and Writer classes. Until Java… Continue Reading java-filewriter
Fallback for Zuul Route 1. Overview Zuul is an edge service (or API gateway) from Netflix that provides dynamic routing, monitoring, resiliency, and security. In this tutorial, we’ll look at how to configure Zuul routes with fallbacks. 2. Initial Setup To begin with, we’ll first set up two Spring Boot… Continue Reading spring-zuul-fallback-route
Work With Me OAuth Deep Dive You’re a good fit here if you’re either already doing OAuth with Spring Security, or you’re starting to try it out but the implementation hasn’t reached production yet. Either way, my focus here is getting OAuth fully implemented into your system, and making sure… Continue Reading work-with-me
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A Quick Guide to @DirtiesContext 1. Overview In this quick tutorial, we’ll learn about the @DirtiesContext annotation. We’ll also show a standard way to use the annotation for testing. 2. @DirtiesContext @DirtiesContext is a Spring testing annotation. It indicates the associated test or class modifies the ApplicationContext. It tells the testing… Continue Reading spring-dirtiescontext
Using Lombok’s @Accessors Annotation 1. Overview It’s pretty typical to have get and set methods in our domain objects, but there are other ways that we may find more expressive. In this tutorial, we’ll learn about Project Lombok‘s @Accessors annotation and its support for fluent, chained, and custom accessors. Before continuing,… Continue Reading lombok-accessors
Authentication with HttpUrlConnection 1. Overview In this tutorial, we’re going to explore how to authenticate HTTP requests using the HttpUrlConnection class. 2. HTTP Authentication In web applications, servers may require clients to authenticate themselves. Failing to comply usually results in the server returning an HTTP 401 (Unauthorized) status code. There… Continue Reading java-http-url-connection