Post-Mortem JVM Crash Analysis with jcmd

A JVM sustaining engineer presents JEP 528, which extends the jcmd diagnostic tool to support post-mortem analysis of JVM crash dumps (core files on Linux, minidumps on Windows). The talk covers existing JVM diagnostic tools (JMX, SA, JFR, native debuggers like GDB), their limitations for crash analysis, and introduces a 'revival helper process' mechanism that loads the crashed JVM binary into the same virtual address space to reconstruct state and execute diagnostic commands against the core file. Supported commands include thread dumps, heap dumps, GC info, class histograms, metaspace info, and class loader stats. The feature targets Linux x64/aarch64 and Windows x64, is under code review, and is aimed for JDK 27.