Multi-Dimensional Arrays

Java 19: Deep Dive into Virtual Threads and Platform Threads

Virtual threads are lightweight threads that reduce the effort of writing and maintaining the high-throughput concurrent application.


Operating Systems have limited say over the efficiency of platform threads. Here comes the JDK which enables the one-to-one relationship between its threads and OS threads and makes better use of platform threads.

Here in Java19, a sharing mechanism has been implemented such that when a virtual thread requires an OS thread to do CPU work but doesn’t hold the OS thread while waiting for other resources. In so meantime this virtual thread is completing a blocking I/O operation in the JDK API, the runtime performs a nonblocking OS call and it will suspend this virtual thread until the operation completes. As the OS thread is now available other virtual threads can perform operations using this OS thread. Essentially virtual threads are sharing the OS thread whenever a blocking I/O operation gets called.

Why a virtual thread and Why not a virtual thread?

It is essentially required to understand when to use the virtual thread and when not to. A virtual thread concept designed for a specific use, i.e. optimize waiting.

Virtual threads do not require or block OS threads, millions of threads can wait patiently for requests to the databases, web services, or file system to finish.

Virtual threads are not faster threads. We can maximize the utilization of external resources using virtual threads thus it provides a larger scale not the speed but improved throughput.

Java 19 introduces two key concepts – Virtual Threads and Platform Threads. Let’s unpack these exciting features.

Virtual Threads

Understanding Virtual Threads in Java 19

Firstly, we examine Virtual Threads, a groundbreaking addition to Java 19. Unlike traditional threads, virtual threads aren’t tied to the underlying hardware. Instead, they are lightweight, easy to spawn, and designed to handle a vast number of I/O bound tasks. They help to manage blocking code, increase throughput, and enhance resource utilization. Virtual threads signify a new paradigm in the way Java handles concurrent tasks.

Platform Threads: The Classic Approach

Next, we explore Platform Threads. Platform threads in Java 19 maintain the legacy of Java’s original threading model. These are the kernel-level threads, directly mapped onto the operating system’s threads. They are suitable for compute-intensive tasks where the number of threads is usually limited by the number of cores. Understanding when to use platform threads and virtual threads can aid in efficient resource allocation.

Seamless Interoperation: Virtual and Platform Threads

One of the major strengths of Java 19’s threading model is the smooth interoperation between virtual and platform threads. Java’s structured concurrency API ensures that both types of threads can work together in harmony, providing a comprehensive toolset for tackling different types of tasks in your Java application.

Java 19 Thread Scheduler: Balancing Act

The thread scheduler in Java 19 is now smarter, thanks to the addition of virtual threads. It dynamically balances between the execution of virtual and platform threads, optimizing the overall performance of your Java application.

Java 19: The Future of Concurrency

With the introduction of virtual threads and the enhancement of platform threads, Java 19 is redefining the way developers approach concurrency. As we embrace these novel features, we can anticipate a shift towards more performant and efficient Java applications.

In conclusion, Java 19’s enhancements to thread handling, particularly the addition of virtual threads and the evolution of platform threads, herald a new era in Java development. It presents an exciting opportunity for developers to optimize performance, resource management, and ultimately, the user experience. Embracing these updates equips developers with the tools to create more robust, responsive, and resource-efficient applications.