JDK 27: Numeric Fields in JSON Thread Dumps – Inside.java

JDK 27 changes the format of JSON thread dumps so that thread identifiers, thread counts, and the process identifier are now emitted as JSON numeric types instead of strings. This affects output from both `com.sun.management.HotSpotDiagnosticMXBean.dumpThreads` and the `jcmd Thread.dump_to_file` command. The change also introduces a `formatVersion: 2` field to help tools detect and handle future format changes. Developers are encouraged to test their tools and scripts against JDK 27 early-access builds and update any JSON parsing logic that expects these fields as strings.