Unlock Java 17 in IntelliJ IDEA 2021.2.1: Pattern Matching, Switch & Speed Tips

1. Java 17 and IDEA 2021.2.1

Java 17 was released today, and IntelliJ IDEA 2021.2.1 supports writing, compiling, and running Java 17 code. Upgrading to the latest IDEA gives a better experience of Java 17’s new capabilities.

1.1 Pattern Matching

In IntelliJ IDEA you can invoke pattern matching for instanceof by pressing Alt+Enter or clicking the light‑bulb icon and selecting “Replace ‘s’ with pattern variable”.

1.2 Unlimited Possibilities of Pattern Matching

Pattern matching for instanceof may seem simple but can unlock many possibilities. By replacing an if statement with a pattern variable and using Collection.removeIf(), you can eliminate a traditional for‑loop.

1.3 Switch Expressions

A video demonstrates several uses of switch expressions, such as concise code, improved semantics, no redundant break statements, and exhaustive iteration.

1.4 Pattern Matching + Switch

Old if‑else chains are hard to read. The new switch structure makes the logic clear, as illustrated below.

2. IDEA 2021.2.1 Freezes?

The author experienced severe lag after upgrading to the latest IDEA version. Disabling and uninstalling rarely used plugins—especially “Code With Me” and “Space”—significantly improved performance, making the IDE feel faster than older versions.

3. Conclusion

The author invites readers to discuss and share IDEA tips and tricks.