Auto-Restart Spring Boot Application On Code Change With Dev Tools

Spring Boot Dev Tools enables auto-restarting a Spring boot application whenever any class is changed in the class path. This is not comparable in speed with the hot swap functionality offered by Jrebel or Spring Loaded, but this is a very simple and easy way to implement and better than manual restart. In this post, I use a simple Spring boot rest echo service to demonstrate how spring boot dev tools can be used to auto restart the application when using Maven on an IDE or Gradle from command line. In either options, the main trigger for a restart is the change to a class file, which means that the change to a Java file has to be compiled either by the IDE in option 1 or by Gradle in option 2.

Passing System Properties and Arguments With Gradle

When using the Gradle application plugin, Gradle spawns a new JVM on the fly, and does not pass the System Properties or Command-line arguments to the new Java process. This post explains how to pass the System properties and command-line arguments when using Gradle application plugin.

Load Environment Specific Properties Files Using Spring

One of the more common aspects of enterprise application development involves environment specific properties files. Some examples include Database configurations or external JMS resources etc. The common way to address this problem is to use multiple properties file an build the Application EAR/WAR/JAR at compile time. Although this works, this solution also means that we maintain different build scripts for different environments, or having some file renames etc. while building the application. Spring profiles address this problem in a more efficient way. Like any other property, using Spring profiles, we can inject the environment profile into Spring and Spring will handle the loading of the appropriate configuration files. In this post, I show how to load environment specific properties files using Spring.

Reactor: Reactive Programming Java 8

One of the more interesting features in the upcoming release of Java 9 is the support for Reactive Programming in Java. At a high-level Reactive programming deals with asynchronous data streams. Reactive streams provides a standard for asynchronous stream processing. Java 9 supports Reactive programming implementing the Reactive Streams specification through the Flow API. But before the release of Java 9, there are ways to implement Reactive programming in Java 8. Reactor and RxJava are a couple of APIs to implement Reactive streams in Java 8. Reactor is used internally by the Spring Framework to it's own Reactive support in version 5. In this post, we will look into Reactor library.