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Composite Primary Keys in JPA 1. Introduction In this tutorial, we’ll learn about Composite Primary Keys and the corresponding annotations in JPA. 2. Composite Primary Keys A composite primary key – also called a composite key – is a combination of two or more columns to form a primary key… Continue Reading jpa-composite-primary-keys
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Filtering Kotlin Collections 1. Overview Kotlin collections are powerful data structures with many beneficial methods that put it over and beyond Java collections. We’re going to cover a handful of filtering methods available in enough detail to be able to utilize all of the others that we don’t explicitly cover… Continue Reading kotlin-filter-collection
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Send Operating System Data into Elastic Stack (ELK Stack) 1. Overview In this quick tutorial, we’ll discuss how to send OS-level metrics into Elastic Stack. As a reference, we’re going to be using an Ubuntu server here. We’ll use Metricbeat to collect data from the Operating System and send them… Continue Reading os-data-into-elastic-stack
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On Kotlin Overview + Introduction to the Kotlin Language Core Concepts + Comprehensive Guide to Null Safety in Kotlin + Guide to the “when\{}” Block in Kotlin + Try-with-resources in Kotlin + Destructuring Declarations in Kotlin + Lazy Initialization in Kotlin + Kotlin and Tail Recursion + Difference Between “==”… Continue Reading kotlin-overview
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Introduction to Spring REST Docs 1. Overview Spring REST Docs generates documentation for RESTful services that is both accurate and readable. It combines hand-written documentation with auto-generated document snippets produced with Spring tests. 2. Advantages One major philosophy behind the project is the use of tests to produce the documentation.… Continue Reading spring-rest-docs
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Guide to DateTimeFormatter 1. Overview In this tutorial, we’ll review the Java 8 DateTimeFormatter class and its formatting patterns. We’re also going to discuss possible use cases for this class. We can use DateTimeFormatter to uniformly format dates and times in an app with predefined or user-defined patterns. 2. DateTimeFormatter with Predefined Instances DateTimeFormatter… Continue Reading java-datetimeformatter
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@Timed Annotation Using Metrics and AspectJ 1. Introduction Monitoring is very helpful for finding bugs and optimizing performance. We could manually instrument our code to add timers and logging, but this would lead to a lot of distracting boilerplate. On the other hand, we can use a monitoring framework, driven… Continue Reading timed-metrics-aspectj
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Java ‘Hello World’ Example 1. Overview Java is a general-purpose programming language that focuses on the WORA (Write Once, Run Anywhere) principle. It runs on a JVM (Java Virtual Machine) that is in charge of abstracting the underlying OS, allowing Java programs to run almost everywhere, from application servers to… Continue Reading java-hello-world
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Java Weekly, Issue 210 Here we go… 1. Spring and Java ===== >> Getting Started with Microservices in SpringBoot [infoq.com] A quick guide to starting your microservices journey in the Spring ecosystem. >> Hibernate Tips: What’s the Difference between JOIN, LEFT JOIN and JOIN FETCH [thoughts-on-java.org] JOIN and LEFT JOIN… Continue Reading java-weekly-210
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Introduction to BouncyCastle with Java Security 1. Overview BouncyCastle is a Java library that complements the default Java Cryptographic Extension (JCE). In this introductory article, we’re going to show how to use BouncyCastle to perform cryptographic operations, such as encryption and signature. 2. Maven Configuration Before we start working with… Continue Reading java-bouncy-castle
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