How do you debug a native image application when standard Java debuggers don't attach?

A native executable is compiled machine code, not JVM bytecode, so a standard jdb/JDWP-based debugger that expects a live JVM to attach to has nothing to connect to.

1. Build with debug info: native-image -g -O0 -jar app.jar embeds source-level debug symbols and disables optimizations that would otherwise make stepping through code confusing.
2. Attach a native debugger: on Linux, GDB can attach directly to the running native-image process and, with the embedded debug info, step through Java source lines, inspect local variables, and set breakpoints much like a native C/C++ program.
3. Use IDE integration: recent versions of IntelliJ IDEA and VS Code support debugging native-image binaries directly using this same GDB-based mechanism, presenting it similarly to a normal Java debugging session.
4. Fall back to JVM-mode debugging for logic-level bugs: since most application logic is identical on JVM and native image, reproducing a bug on the regular JVM with jdb first is often faster, reserving native-only debugging for issues specific to native-image behavior (like a missing reflection entry).