Capture Files

When values are too large for one line, the full event goes to a capture file.

When the full JSON line exceeds the threshold (default 500 characters) or contains newlines, the complete event is written to a capture file. The console gets a summary line instead.

Console summary

JACKKNIFE {"event":"call","time":"2.3ms","class":"Join","method":"join","status":"returned","file":"target/jackknife/captures/capture-0012.txt"}

The summary line includes enough to triage without opening the file:

  • time — how long the call took
  • class and method — what was called
  • status — "returned" or "thrown"
  • exception — exception type (only when status is "thrown")
  • file — path to the capture file

Scan timing and status across all calls. Open only the ones that matter.

Capture file contents

The capture file contains the COMPLETE JSON event with all fields — full args array, full return value or exception, everything that would have been on the console line if it fit.

File naming and location

Files are named capture-NNNN.txt, numbered sequentially starting from capture-0001.txt. Default location is target/jackknife/captures/.

The file reference in the summary line is a path you can read directly:

cat target/jackknife/captures/capture-0012.txt