Add Java Threads documentation (incomplete)

[Copilot]

Task: Create comprehensive Java Threads documentation with 30+ examples covering thread lifecycle, synchronization, executors, and real-world patterns.

Status: Incomplete

Initial exploration completed:

• Identified target file: concurrency/threads.md (currently empty)
• Analyzed existing documentation style from concurrency.md and completablefuture.md
• Documented required Java 25 patterns (implicit imports, instance main methods, var inference)

Blocked

Tool execution issues prevented writing content to the file. The documentation structure was planned:

• Introduction (threads vs processes, concurrency vs parallelism)
• Thread lifecycle and states table
• Creating threads (Thread class, Runnable, ExecutorService, CompletableFuture)
• Synchronization primitives
• 30+ progressive examples
• Best practices and pitfalls

Note

The existing concurrency.md already contains ~50 comprehensive examples covering most of the requested topics. Consider whether threads.md should be a focused subset or if concurrency.md already satisfies the requirement.

Original prompt

On threads.md, Generate a detailed technical documentation about Java Threads.
The documentation must be structured, well-organized, and beginner-friendly, while still providing depth for intermediate learners.

Coverage Requirements:

1. Introduction to Threads

   • Define what a thread is in Java.
   • Explain the difference between a process and a thread.
   • Clarify the concept of concurrency vs parallelism.

2. Thread Basics

   • Meaning of a thread in Java.
   • Basic concepts: lifecycle, states (new, runnable, running, waiting, terminated).
   • Thread priorities and scheduling.

3. Usage of Threads

   • Why threads are used in Java applications.
   • Common use cases: multitasking, background tasks, asynchronous operations, improving responsiveness.

4. How to Run a Thread

   • Creating threads using Thread class.
   • Implementing Runnable interface.
   • Using ExecutorService and thread pools.
   • Modern approaches (e.g., CompletableFuture).

5. Why Use Threads

   • Benefits: efficiency, responsiveness, resource utilization.
   • Risks: race conditions, deadlocks, synchronization issues.
   • Best practices for safe thread usage.

6. Examples

   • Provide at least 30 practical examples of Java thread usage.
   • Examples should range from simple to advanced:
     • Creating and starting a thread.
     • Using Runnable.
     • Thread sleep and join.
     • Synchronization with synchronized keyword.
     • Using wait() and notify().
     • Thread pools with Executors.
     • Scheduled tasks.
     • Callable and Future.
     • Atomic variables.
     • Parallel streams.
     • CompletableFuture usage.
     • Real-world scenarios (e.g., downloading files concurrently, producer-consumer problem, chat server simulation).
   • Each example must include code snippets and short explanations.

7. Conclusion

   • Summarize key takeaways.
   • Highlight best practices for using threads safely and effectively in Java.

Formatting Requirements:

• Use clear section headings.
• Include tables or diagrams where helpful (e.g., thread lifecycle).
• Code examples must be properly formatted and runnable.
• Provide concise explanations after each example.
• Maintain a consistent style throughout the documentation.

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