A comprehensive guide providing essential design principles and best practices for Java development

Java 25 development patterns for the crypto-scout ecosystem including microservices, ActiveJ, and async I/O

Implement error-as-value pattern in Java using Result type for type-safe error handling. Use this skill when implementing error handling without exceptions, converting try-catch to Result pattern, or designing type-safe error handling in Java applications. Particularly useful for functional programming style, API design, and when errors are expected and recoverable.

Expert-level Java development with Java 21+ features, Spring Boot, Maven/Gradle, and enterprise best practices

Master core Java programming - syntax, OOP, collections, streams, and exception handling

Master Gradle - Kotlin DSL, task configuration, build optimization, caching

Maven build system, dependency management, and Java project configuration assistance.

Build microservices - Spring Cloud, service mesh, event-driven, resilience patterns

This skill should be used for Java/Spring patterns, dependency injection, streams, Optional, Kotlin, Spring Boot, Maven, Gradle, JVM backend

Build production Spring Boot applications - REST APIs, Security, Data, Actuator

Java Spring Boot 开发规范和最佳实践指南。适用于企业级Java后端开发，涵盖项目架构、编码规范、安全实践、性能优化等全方位内容。

Write vanilla JavaScript for Web Components with functional core, imperative shell. Use when creating JavaScript files, building interactive components, or writing any client-side code.

Core JavaScript language features, patterns, and best practices including ES6+ syntax, async/await, closures, prototypes, and modern development patterns

Write modern, performant, type-safe JavaScript and React code following current best practices.

JavaScript and TypeScript development with ES6+, Node.js, React, and modern web frameworks. Use for frontend, backend, or full-stack JavaScript/TypeScript projects.

jellyfin

Investigates JetBrains IntelliJ Platform theme properties by searching source code. Use when user asks about UI theming, icon colors, tab spacing, component styling, or needs to find what properties are themeable vs hardcoded in IntelliJ-based IDEs.

Use when building Android UIs with Jetpack Compose, managing state with remember/mutableStateOf, or implementing declarative UI patterns.

Use Jina AI APIs for converting URLs to LLM-friendly Markdown (Reader) and searching the web (Search).

Manage Jira Agile boards and sprints. Use when listing boards, creating sprints, or moving issues to/from sprints.

Organize and manage Jira boards, issues, and sprints. Use when the user wants to: (1) List, create, update, or transition Jira issues, (2) View or manage sprints, (3) Assign issues or change status, (4) Query issues with JQL, (5) Manage Jira boards. Requires environment variables JIRA_URL, JIRA_USERNAME, JIRA_API_TOKEN, and optionally JIRA_PROJECTS_FILTER.

jira-builders

Interact with Jira from the command line to create, list, view, edit, and transition issues, manage sprints and epics, and perform common Jira workflows. Use when the user asks about Jira tasks, tickets, issues, sprints, or needs to manage project work items.

Create, update, and manage Jira issues from natural language. Use when the user wants to log bugs, create tickets, update issue status, or manage their Jira backlog.

Look up a Jira issue by key. Shows summary, status, assignee, priority, and link.

Prepare a Jira task with technical enrichment, subtask creation, and work breakdown structure.

Manage Jira projects. Use when listing projects, getting project configuration, retrieving issue types, or managing components and versions.

Creates well-structured JIRA tickets in the HYPERFLEET project with required fields including What/Why/Acceptance Criteria, story points, and activity type. Activates when users ask to create a ticket, story, task, or epic.

Look up Jira ticket details including summary, type, and description. Use this to fetch ticket context for branch naming, PR creation, or understanding requirements.

Merges two separate Jujutsu (jj) repositories into one. Use when combining repos, rebasing one repo onto another, or recovering from diverged histories.

Structured TODO commit workflow using JJ (Jujutsu). Use to plan tasks as empty commits with [task:*] flags, track progress through status transitions, manage parallel task DAGs with dependency checking. Enforces completion discipline. Enables to divide work between Planners and Workers. **Requires the working-with-jj skill**

Jujutsu is a next-generation version control system that uses Git repositories as storage while providing a fundamentally different and more powerful user experience. This skill includes the complete

Jujutsu (jj) is a Git-compatible distributed version control system with a fundamentally better mental model. It treats the working copy as a commit, distinguishes changes from revisions, and provides

Enables JMAP email operations using Node.js and jmap-jam library. Use when working with JMAP email servers, FastMail, Cyrus IMAP, Stalwart Mail Server, or when user mentions email search, reading, sending, or mailbox management.

JMicron Technology MPN encoding patterns, series identification, and handler guidance. Use when working with storage controller ICs or JMicronHandler.

Эксперт по job descriptions. Используй для создания вакансий, требований и EVP.

Analyze fit between job requirements and background using lexicons - identifies gaps, develops reframing strategies, creates cover letter plan

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JOIN.com Bewerbungsmanagement - neue Bewerbungen anzeigen, Gehaltsvorstellungen prüfen, PDFs automatisch zu Google Drive hochladen. Use when user asks about applications, candidates, job applications, Bewerbungen, or JOIN.

Jotai atomic state management patterns. Use when implementing fine-grained reactive state.

Implement reactive state management with Jotai atoms in Electron renderer. Use when creating atoms, implementing real-time updates via IPC, or setting up hybrid stream + HTTP fallback patterns. Covers event subscription optimization, debouncing, and Suspense integration.

Manages React state with Jotai including atoms, derived atoms, async atoms, and utilities. Use when building React applications needing atomic state, bottom-up state management, or fine-grained updates.

Interact with the Journal API to manage projects, documents, tasks, and workspaces. Use when the user mentions journal, projects, documents, tasks, workspaces, task identifiers like JO-123, or needs to access Journal data.

Use when creating animations that evoke happiness, surprise, or delightful moments in the user experience.

Use when consuming jp-ui in an app: installation, CSS/theme setup, component selection, and token usage; guide Codex to the jp-ui docs and types for implementation details.

Deploy jpbailes.com to GCP Cloud Run or trigger Render failover

Comprehensive toolkit for building applications with JPYC (Japanese Yen Pegged Coin). Use this skill when developing with JPYC token, implementing payment features, integrating JPYC SDK, deploying JPYC contracts to Base Sepolia, or building DApps with JPYC. Supports both JPYC SDK v1 usage and direct Solidity smart contract development with Hardhat, ethers.js, viem, Next.js, and React.

Best practices for jQuery AJAX with JSON data handling including sending/receiving JSON, error handling, security (CSRF protection, XSS prevention), promise patterns, caching, and modern alternatives. Use when working with jQuery AJAX requests, implementing JSON APIs, troubleshooting AJAX issues, or migrating from jQuery to Fetch API.

Hoist RegExp creation outside render or memoize with useMemo(). Apply when using regular expressions in React components or frequently called functions.