Top 5 Spring 6 New Features Java Developer Should Learn

Hello guys, if you are wondering what is New in Spring Framework 6 release and what new feature it has got or what does it support now then you have come to the right place. In this article, I will share 5 key changes from Spring Framework 6 which are worth knowing for Every Java developer. Before we get to the top 5 features of Spring that you need to definitely learn, let me tell you a bit more about what Spring Framework really is. Spring is basically a framework that can be used for developing various types of applications with the help of Java platforms. It also provides support for the Plain Old Java Objects, also known as POJOs, that developers can use for easily creating the Java SE Programming Model with full and partial Java EE.

5 Features Of Spring Java Programmer Should Learn

Spring basically provides a framework that incorporates a lot of useful technologies like Aspect-oriented programming, Dependency Injection, and Plain Old Java Objects. It also allows developers to create a Java method that runs in a database transaction with no help from transaction APIs. Developers can also create a local Java method that defines a remote procedure with no help from remote APIs.

Another thing you need to know is that Spring is a lightweight framework. It has the best mechanisms that you can use for different frameworks like Struts, Hibernate, EJB, JSF, and Tapestry. It also helps you in solving complex real-time problems. It consists of a lot of modules like WEB MVC, IOC, DAO, and AOP. 

1. Spring Starter Dependencies

One of the most exciting things about Spring 6 is the release of Spring Boot Starter dependencies. You can use Spring Starter for declaring your starter dependencies. Maven will look at this and then pull down all the other related dependencies. 

You also have the option of selecting any other dependency. This is pretty straightforward thanks to the new changes that have been introduced in the new version of the Spring Starter infrastructure. 

Spring Observability is another new feature that we will talk about in detail later. 

It is a new project that is built on Spring Cloud Sleuth. Using this, you can efficiently record application metrics using Micrometer. It is also possible to implement tracing using providers like OpenZipKin and OpenTelemtry. 

2. Web Applications

With the release of Spring 6, you will need to make sure that you are upgraded to Tomcat 10, Jetty 11, and the new version of Undertow. Spring 6 has also removed some of the old Servlet-based integrations. 

These include stuff like Commons FileUpload, Tiles, FreeMarker, and JSP support. It is highly recommended to use StandardServletMultipartResolver for parting the file uploads. If required, you can also use the FreeMarker template views. 

Spring 6 focuses more on web architectures that are REST-oriented. 

Also, if you are using the new Spring 6, it will not detect either Spring MVC or Spring WebFlux if you are using the @RequestMapping annotation. 

What this essentially means is that interface-based AOP proxying for certain web controllers may no longer work. Additionally, you will have to make sure that you enable class-based proxying for the web controllers. You can also mark your controller using @Controller.  

Pattern Matching was first introduced in Project Amber. Since then, it has become an important part of the Java language. It is very helpful in simplifying the code for instanceof evaluations. Pattern matching can be used directly with instanceof. See the following example:

if (obj instanceof String s) {
    System.out.println(s.toLowerCase());
}

You can also use it inside a switch-case statement. Check out the following example:

static double getDoubleUsingSwitch(Object o) {
    return switch (o) {
        case Integer i -> i.doubleValue();
        case Float f -> f.doubleValue();
        case String s -> Double.parseDouble(s);
        default -> 0d;
    };
}

You can also use sealed classes to limit inheritance. This can be done by specifying allowed subclasses. See the given example: 

public abstract sealed class Pet permits Dog, Cat {}

3. Core Container, Data Access, And Transactions

There are some important changes to the Core COntainer that you need to keep in mind. In Spring 6, you can find the @Inject annotation in jakarta.inject. This is an annotation that is included in the JSR-330 annotations collection. 

There are also JSR-250 annotations like @PostConstruct and @PreDestroy that can be found in jakarta.annotation. As of now, Spring also detects the javax equivalents of these annotations. 

If you are using the new Spring Framework 6, you will also need to make sure that you are upgrading to Hibernate ORM 5.6.x. 

You can do this using the hibernate-core-jakarta artifact. This essentially means that if you are coding against Hibernate you will need to change from javax.persistance imports to jakarta.persistence. 

You will also need to include the corresponding Hibernate Validator generation dependency version 7.0.x. This is based on jakarta.validation. 

4. Java 17

You may be rolling your eyes at this one, but just hear me out. I know that there was already support for Java 17, but this LTS version is getting the baseline now. If you are looking to migrate from LTS version 11, and if you are a Java developer, the new language features will definitely benefit you. 

Java records can also be used as a quick way for creating data carrier classes. 

This includes classes whose aim is to contain data and carry it in between modules. They are also known as POJOs and DTOs.  It is pretty easy to create immutable DTOs:

public record Person (String name, String address) {}

But you need to be really careful when you are combining DTOs with Bean Validation. This is because there are some validation constraints that are not supported based on constructor arguments. 

5. Observability

In Spring 6, there is also an Observability initiative which also includes a new Micrometer Observation API along with the former Spring Cloud Sleuth project which has been migrated to Micrometer tracing. This increases the efficiency by recording application metrics with Micrometer. It can also implement tracing through different providers like OpenZipKin or OpenTelemetry. 

In addition to all of this, there is also an auto-configuration feature in Spring Boot 3. 

That's all about the 5 features from Spring Framework 6 which are worth knowing and learning for Java developers. If you liked this list of the 5 best new Spring 6 features you need to learn, feel free to share it with your friends and family. You can also drop a comment if you have any doubts about Spring or Hibernate and we will get back to you in an instant. 

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Thanks for reading this article so far; if you find these Spring framework 6 new features useful, please share them with your friends and colleagues.

P. S. - If you want to learn about Spring Boot and look for a free Spring Boot online course, I also recommend you join the Introducing Spring Boot (FREE ) class by Dan Vega on Udemy. It's one of the best free courses to learn Spring Boot for Java developers.