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The DAO Pattern in Java 1. Overview The Data Access Object (DAO) pattern is a structural pattern that allows us to isolate the application/business layer from the persistence layer (usually a relational database, but it could be any other persistence mechanism) using an abstract API. The functionality of this API… Continue Reading java-dao-pattern
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Guide to the this Java Keyword 1. Introduction In this tutorial, we’ll take a look at the this Java keyword. In Java, this keyword is a reference to the current object whose method is being called. Let’s explore how and when we can use the keyword. 2. Disambiguating Field Shadowing The keyword… Continue Reading java-this
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Mapping Entitiy Class Names to SQL Table Names with JPA 1. Introduction In this short tutorial, we’ll learn how to set SQL table names using JPA. We’ll cover how JPA generates the default names and how to provide custom ones. 2. Default Table Names The JPA default table name generation… Continue Reading jpa-entity-table-names
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Convert JSON to a Map Using Gson 1. Introduction In this quick tutorial, we’ll learn how to convert a JSON string to a Map using Gson from Google. We’ll see three different approaches to accomplish that and discuss their pros and cons – with some practical examples. 2. Passing Map.class… Continue Reading gson-json-to-map
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Derived Query Methods in Spring Data JPA Repositories 1. Introduction For simple queries, it’s easy to derive what the query should be just by looking at the corresponding method name in our code. In this tutorial, we’ll explore how Spring Data JPA leverages this idea in the form of a… Continue Reading spring-data-derived-queries
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Auto-import Classes in IntelliJ 1. Overview This brief tutorial will describe each option of IntelliJ IDEA’s ‘auto-import’ feature. 2. Auto-import There are several options in IntelliJ IDEA that we may configure in Settings > Editor > Auto Import: Let’s review each of these options. 2.1. Show Import Popup When enabled, IDEA… Continue Reading intellij-auto-import-class
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Spring Boot Gradle Plugin 1. Overview The Spring Boot Gradle plugin helps us manage Spring Boot dependencies, as well as package and run our application when using Gradle as a build tool. In this tutorial, we’ll discuss how we can add and configure the plugin, and then we’ll see how… Continue Reading spring-boot-gradle-plugin
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Method Constraints with Bean Validation 2.0 1. Overview In this article, we’ll discuss how to define and validate method constraints using Bean Validation 2.0 (JSR-380). In the previous article, we discussed JSR-380 with its built-in annotations, and how to implement property validation. Here, we’ll focus on the different types of… Continue Reading javax-validation-method-constraints
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Count Occurrences of a Char in a String 1. Overview There are many ways to count the number of occurrences of a char in a String in Java. In this quick article, we’ll focus on a few examples of how to count characters, first, with the core Java library and… Continue Reading java-count-chars
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Deploying Web Applications in Jetty 1. Overview In this article, we will do a quick overview of the Jetty web server and then cover various approaches to deploying a WAR file. Jetty is an open source Java HTTP web server and a servlet container. Jetty is more commonly used in… Continue Reading deploy-to-jetty
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