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name: jdb-debugging description: "Debug local JVM applications using jdb via tmux. Use when user asks to debug a running Java/Scala/Kotlin application, attach to a debug port, set breakpoints, step through code, or inspect variables."

JDB Debugging via tmux

Debug running JVM applications using jdb controlled through tmux panes.

Setup

With dedicated pane (preferred): User provides pane ID (e.g., %265)

Copytmux send-keys -t %265 "jdb -attach PORT" Enter
sleep 2
tmux capture-pane -t %265 -p

With new session:

Copytmux new-session -d -s jdb "jdb -attach PORT"
sleep 2
tmux capture-pane -t jdb -p

Commands

All commands follow this pattern:

Copytmux send-keys -t PANE "COMMAND" Enter
sleep 0.5
tmux capture-pane -t PANE -p

Breakpoints

Copy# Simple method (non-overloaded)
stop in com.example.MyClass.myMethod

# Overloaded method - first list methods to find signature
methods com.example.MyClass
# Then use exact signature
stop in com.example.MyClass.execute(java.lang.Object)

# Line breakpoint (often fails with Scala due to line mismatch)
stop at com.example.MyClass:42

Navigation

Inspection

Breakpoint Management

Scala/Kotlin Notes

• Line breakpoints often fail - use method breakpoints instead
• For overloaded methods, use methods ClassName to find exact JVM signature
• list command typically fails (source not found) but inspection commands work fine

Cleanup

Copy# Session approach
tmux kill-session -t jdb

# Pane approach - just exit jdb
tmux send-keys -t %265 "quit" Enter