How to Stay Ahead as a Java Developer: Tips for JDK 21, Spring Boot 3.2, and Beyond

Recently I talked with an experienced Java developer about JDK 21 and Spring Boot 3.2 observability improvements, and whether he had already migrated from 17 to 21 and to Spring Boot 3.2.

He shared that he feels his skills are getting rusty after focusing on IntelliJ plugin development for two years, and he wants to catch up by learning everything from Java 17 to 21, especially with Java 22 and Spring 3.2 on the horizon. He is excited about upcoming features such as non‑Java interop and access to LAPACK and BLAS libraries, which open new opportunities for Java.

He still develops on version 17, knows many companies still use Java 8, but wants to experience the time‑ and memory‑saving possibilities of the new specifications, especially lambda support. After discussing with a friend, he posted on Reddit’s r/ExperiencedDevs to see if other developers feel the same and to gather suggestions for boosting confidence as Java developers.

The feedback was positive, and he decided to compile the tips for developers who feel they are falling behind.

Tips for becoming a better Java developer

Upgrade your JDK version; JetBrains IDEs will automatically suggest most new changes and highlight unused language features.

Learn Kotlin; it offers fresh perspectives and can ease a future job switch. Many Java 17/21 features resemble Kotlin’s, except for null‑safety, and they remain backward compatible.

Embrace feeling out‑of‑practice as a growth opportunity; dive into the parts of the stack you find most intimidating.

Explore how other languages/frameworks solve problems; cross‑pollinating ideas can simplify your work.

Get familiar with Project Loom, a fundamental change in Java.

Read about Structured Concurrency in JDK 21 (e.g., JEP 428) – a major leap in concurrent programming.

Virtual Threads – the final version in JDK 21, offering Go‑like high‑performance async/reactive programming without complexity.

Structured Concurrency – still preview in JDK 21, comparable to Go’s errgroup but with a better Java API.

Watch Oracle’s Java Day presentations for a broad overview of new features; read the detailed reports when a feature looks useful.

Learn Groovy first, then Scala; Scala often feels more enjoyable than Java and can command higher salaries, though job opportunities are fewer.

Check the “Categorized list of all Java and JVM features since JDK 8 to 21” for useful and minor additions (e.g., unnamed variables, sealed classes).

Implement continuous feedback in your development cycle; collect runtime data to detect issues before production.

Consider Ktor: easier upgrades due to lack of inter‑dependency, no “magic”, better performance than Spring Kafka, smaller dependency tree (about one‑third the size), and near‑instant startup.

Start a side project; sites like https://codingchallenges.fyi/ provide good ideas.

Take observability seriously; become familiar with tools such as JVisualVM, JProfiler, and continuous‑feedback solutions.

Stay connected with the Java community – join JUGs, attend meetups, and share knowledge.

Follow expert blogs and social media; examples include Foojay, Digma, Red Hat solution architect Piotr Mińkowski, Spring advocate Josh Long, and others.

Subscribe to Rodrigo Graciano’s weekend reading list (https://graciano.dev/) for top Java articles.

Remember that feeling “rusty” is normal; embrace it as a sign you’re ready to improve.

Source: Reddit

Final thoughts

I hope some of you can relate and find these suggestions valuable, and that the supportive community is always ready to help.

Author: 万能的大雄