Create an ReactJS application that displays a real-time dashboard with live updates using WebSocket technology. The dashboard should display metrics such as CPU usage, memory usage, disk usage, and network traffic. Implement a feature to toggle dark mode using a toggle button. Use Context API to manage global state for dark mode.

Implement a NodeJS RESTful API using Express that provides endpoints to manage a list of books. Each book has properties: id, title, author and publishedDate. Create GET, POST, PUT and DELETE methods to manage books in the list. Use body-parser middleware for parsing request bodies.

Implement a concurrent web scraper in Golang using the colly library that fetches data from multiple URLs simultaneously and stores extracted information into a database. The scraper should target websites with table-based content, extract rows and cells, clean the scraped data, and store it in a structured format (e.g., JSON).

Create a multithreaded server in Java using java.net.ServerSocket that serves HTTP requests and responses (using java.io.InputStream and java.io.OutputStream). Implement basic routing where GET requests to the root path return a welcome message, while GET requests to /user returns user data in JSON format. Use Jackson library for JSON conversion.