Virtual Threads Take the Responsibility for Allocating System Resources Out of Your Application Code and Into the JVM
How Virtual Threads Work
Virtual threads introduce an abstraction layer between operating-system processes and application-level concurrency. In other words, virtual threads can be used to schedule tasks that the Java virtual machine orchestrates, so the JVM mediates between the operating system and the program. Figure 1 shows the architecture of virtual threads.
Using Java Virtual Threads: A Demo
To demonstrate how virtual threads work, let’s consider a simple example. We will create multiple virtual threads to handle concurrent tasks, showcasing how they reduce the complexity of managing system resources.
Two Ways to Use Virtual Threads
There are primarily two ways to leverage virtual threads in Java:
- Using the Executor API: This allows you to manage virtual threads with familiar constructs.
- Direct Creation and Management: You can directly create and manage virtual threads without an executor.
Best Practices for Virtual Threads
To make the most of virtual threads, consider these best practices:
- Avoid Blocking Operations: Since virtual threads are designed to handle a large number of tasks concurrently, avoid operations that block their execution.
- Use Structured Concurrency: This helps in managing multiple virtual threads effectively and improves readability and maintainability.
- Monitor and Profile: Regularly monitor and profile your application to ensure optimal performance.
Refactoring with Virtual Threads
Refactoring your existing code to use virtual threads can lead to significant performance improvements. Focus on identifying parts of your code where concurrency management is crucial and where virtual threads can offer a more efficient solution.
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Explore more about virtual threads, including advanced usage patterns and case studies, to fully understand their potential and how they can transform your Java applications.
Virtual threads are a major change to the JVM. For application programmers, they represent an alternative to asynchronous-style coding using techniques like callbacks or futures. All told, we could see virtual threads as a pendulum swing back towards a synchronous programming paradigm in Java, when dealing with concurrency. This is roughly analogous in programming style (though not at all in implementation) to JavaScript’s introduction of async/await. In short, writing correct asynchronous behavior with simple synchronous syntax becomes quite easy—at least in applications where threads spend a lot of time idling.