What Java version is used in the project? What has changed when transitioning from 17 to 21?

The project uses Java 17, which is an LTS version with long-term support. When transitioning from Java 17 to Java 21, the following changes and improvements are expected:

• New language features: improvements in pattern matching, expansion of record class capabilities, enhancements in nullability and type system.
• Performance: JVM optimizations, improvements in garbage collectors (e.g., enhancements in ZGC or Shenandoah).
• Incubating and preview features: new APIs and capabilities that may become standard in future versions.
• Security enhancements: updated security and encryption mechanisms.

The transition requires compatibility checks of code and libraries, as well as performance and stability testing. It is important to utilize the new features of Java 21 where justified to improve the quality and efficiency of development.