Java 25 introduces significant improvements including Scoped Values as a better alternative to ThreadLocal, unified Key Derivation Function API for cryptography, module import declarations to reduce boilerplate, flexible constructor bodies allowing code before super() calls, and compact main methods. The release also removes 32-bit x86 support, adds compact object headers for memory efficiency, enhances Shenandoah garbage collector with generational support, and improves JFR profiling with cooperative sampling and method timing features.