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JPA Join Types
1. Overview In this tutorial, we’ll look at different join types supported by JPA. For that purpose, we’ll use JPQL, a query language for JPA. 2. Sample Data Model Let’s look at our sample data model...
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InputStream to String in Kotlin
1. Overview In this brief tutorial, we’ll find out how to read an InputStream into a String. Kotlin provides an easy way to perform the conversion. However, there are still some nuances to consider...
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Introduction to Flowable
1. Overview Flowable is a business process engine written in Java. In this tutorial, we’ll go through the details of business processes and understand how we can leverage the Flowable Java API to...
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JPA @Embedded And @Embeddable
1. Overview In this tutorial, we’ll see how we can map one entity that contains embedded properties to a single database table. So, for this purpose, we’ll use the @Embeddable and @Embedded annotations...
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Java Weekly, Issue 277
Here we go… 1. Spring and Java >> Going Reactive with Spring, Coroutines and Kotlin Flow [spring.io] A quick guide to leveraging the Spring reactive stack in an imperative way using Kotlin...
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Spring Data JPA Projections
1. Overview When using Spring Data JPA to implement the persistence layer, the repository typically returns one or more instances of the root class. However, more often than not, we don’t need all the...
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Guide to Guava Multiset
1. Overview In this tutorial, we’ll explore one of the Guava collections – Multiset. Like a java.util.Set, it allows for efficient storage and retrieval of items without a guaranteed order. However,...
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Spring Data JPA and Null Parameters
1. Overview In this article, we’ll show the ways of handling null parameters in Spring Data JPA. In some cases, when we search for records by parameters we want to find rows with null as the field...
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Setting the Log Level in Spring Boot when Testing
1. Overview In this tutorial, we’ll show how to set the log level when running tests for a Spring Boot application. Although we can mostly ignore the logs while our tests are passing, choosing the...
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Spring Boot With H2 Database
1. Overview In this tutorial, we’ll explore using H2 with Spring Boot. Just like other databases, there’s full intrinsic support for it in the Spring Boot ecosystem. 2. Dependencies So, let’s begin...
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How to Configure Spring Boot Tomcat
1. Overview Spring Boot web applications include a pre-configured, embedded web server by default. In some situations though, we’d like to modify the default configuration to meet custom requirements....
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Spring Data Web Support
1. Overview Spring MVC and Spring Data each do a great job simplifying application development in their own right. But, what if we put them together? In this tutorial, we’ll take a look at Spring...
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Anonymous Classes in Java
1. Introduction In this tutorial, we’ll consider anonymous classes in Java. We’ll describe how we can declare and create instances of them. We’ll also briefly discuss their properties and limitations....
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Persisting Maps with Hibernate
1. Introduction In Hibernate, we can represent one-to-many relationships in our Java beans by having one of our fields be a List. In this quick tutorial, we’ll explore various ways of doing this with a...
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Types of SQL Joins
1. Introduction In this tutorial, we’ll show different types of SQL joins and how they can be easily implemented in Java. 2. Defining the Model Let’s start by creating two simple tables: CREATE TABLE...
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Spring Data JPA Repository Populators
1. Introduction In this tutorial, we’ll explore Spring JPA Repository Populators with a quick example. The Spring Data JPA repository populator is a great alternative for data.sql script. Spring Data...
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Groovy def Keyword
1. Overview In this quick tutorial, we’ll explore the concept of the def keyword in Groovy. It provides an optional typing feature to this dynamic JVM language. 2. Meaning of the def Keyword The def...
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Generic Constructors in Java
1. Overview We previously discussed the basics of Java Generics. In this tutorial, we’ll have a look at Generic Constructors in Java. A generic constructor is a constructor that has at least one...
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Java Weekly, Issue 277
Here we go… 1. Spring and Java >> Going Reactive with Spring, Coroutines and Kotlin Flow [spring.io] A quick guide to leveraging the Spring reactive stack in an imperative way using Kotlin...
View ArticleClik here to view.
JPA @Embedded And @Embeddable
1. Overview In this tutorial, we’ll see how we can map one entity that contains embedded properties to a single database table. So, for this purpose, we’ll use the @Embeddable and @Embedded annotations...
View Article