Manage the JavaFX Application lifecycle, primary stage setup, startup sequencing, and shutdown behavior.
SkillScore95Maintained
Automatic
◆Frontend / UI pack
Last verified 8/4/2026
What it changes
Passed 21 of 22 test cases with the skill, and 19 of 22 without it.
Without skill86%
With skill95%
Checks it passed that the model alone missed
Constructs the Scene inside the start method rather than the init method
Initializes the ExecutorService in the init method instead of the start method
2 fixed19 passed either way1 still failing0 broke
Pass-rate lift
+9 pp
Tokens
-10%
Agent turns
0%
Response time
-22%
Model gemini-3.6-flashMeasured 8/4/2026v121 of 22 cases passed with skill
Tokens, turns and time describe resource use, not a dollar price.
See it in action
One of 2 test cases the skill fixed. Same model, same prompt, with and without the skill.
1 of 2
Prompt
I am writing a JavaFX application class that needs a background ExecutorService for async tasks. I want to initialize the thread pool inside start(Stage stage) right before setting up the scene. Show me where and how to initialize the ExecutorService in the Application lifecycle.
What was checked, without and with the skill
Checked
Without skill
With skill
Initializes the ExecutorService in the init method instead of the start method
Missed
Passed
case-01 · gemini-3.6-flash · 8/4/2026 · answers are capped and redacted
What's inside
The instructions your model reads when the skill loads.
SKILL.md54 linessingle file
JavaFX Application Lifecycle
Use this skill when the application already exists or the question is specifically about
Application.init(), start(Stage), stop(), or primary-stage ownership rather than initial
scaffolding.