Upgraded to the Shiny Java 17? Now What?

Photo by Wenqi at PA Grand Canyon

So your boss told you to upgrade your Spring Boot microservices to Java 17, you did it, all went well! From Java 8 to Java 17, a big jump! What changed? You wonder. What does this upgrade mean for us Java developers in our day to day programming life? Well, let’s take a closer look.

Released on September 15, 2021, Java 17 is the latest LTS (long-term support release) for the Java SE platform. From Java 8 to Java 17, there have been 194 JDK Enhancement Proposals (JEPs) introduced, each of which brings some improvement to the platform. Let’s pick a few to explore.

· Sealed Classes
· Switch Expressions
· Pattern Matching for Switch (Preview)
· Pattern Matching for instanceof
· Text Blocks
· Record Classes
· Meaningful NPE
· Introduction of var
· New String Methods
· Collection Factory Methods

Sealed Classes

Sealed classes or interfaces can restrict which classes or interfaces can extend or implement them. It’s done so by using the sealed modifier, example below:

public abstract sealed class Tree
 permits Maple, Willow, Dogwood, Oak{ … }