JDK 28 finalizes structured concurrency and AOT code cache

JDK 28, due in March 2027, makes structured concurrency final with JEP 543 after seven preview rounds. JEP 544 adds compiled native code to the AOT cache, cutting startup time by 65–80% across five framework benchmarks.

• StructuredTaskScope is final in JDK 28, expected in March 2027
• AOT cache of compiled code cuts startup by 65–80%
• ZGC gets adaptive heap sizing (JEP 546) and faster warm-up (JEP 545)
• JSON API ships in JDK 28 as the jdk.incubator.json module