Class VirtualThreadFactory

java.lang.Object
express.mvp.myra.transport.VirtualThreadFactory
All Implemented Interfaces:
ThreadFactory
public final class VirtualThreadFactory extends Object implements ThreadFactory
Thread factory that creates virtual threads with configurable naming and properties.

This factory creates lightweight virtual threads (Project Loom) that are ideal for I/O-bound operations where blocking is acceptable and millions of concurrent tasks need to be handled efficiently.

Virtual Threads vs Platform Threads

Thread Type Comparison
AspectVirtual ThreadsPlatform Threads
Memory~1KB initial stack~1MB stack
Creation cost~1μs~1ms
Context switch~100ns (continuation)~10μs (kernel)
Max concurrentMillionsThousands
Blocking impactYield to carrierBlock OS thread

Use Cases

  • Callback processing: Handle completion callbacks without blocking I/O thread
  • Request handling: One virtual thread per incoming request
  • Fan-out operations: Concurrent calls to multiple services
  • I/O multiplexing: Wait on multiple channels without selector complexity

Usage Example

VirtualThreadFactory factory = new VirtualThreadFactory("io-worker");
ExecutorService executor = Executors.newThreadPerTaskExecutor(factory);

// Each task runs on its own virtual thread
executor.submit(() -> {
    // Blocking is fine - virtual thread yields to carrier
    channel.read(buffer);
    processData(buffer);
});

Thread Safety

This class is thread-safe. Multiple threads can call newThread(Runnable) concurrently.

See Also:

  • Constructor Details

    • VirtualThreadFactory

      public VirtualThreadFactory(String namePrefix)
      Creates a virtual thread factory with the given name prefix.

      Created threads will be named "{prefix}-{counter}" and will be daemon threads.

      Parameters:
      namePrefix - the prefix for thread names

    • VirtualThreadFactory

      public VirtualThreadFactory(String namePrefix, boolean daemon)
      Creates a virtual thread factory with configurable daemon status.
      Parameters:
      namePrefix - the prefix for thread names
      daemon - whether created threads should be daemon threads

  • Method Details

    • newThread

      public Thread newThread(Runnable runnable)
      Creates a new virtual thread that will execute the given runnable.

      The thread is not started by this method - the caller must start it.

      Specified by:
      newThread in interface ThreadFactory
      Parameters:
      runnable - the task to execute
      Returns:
      a new virtual thread (not started)

    • getThreadCount

      public long getThreadCount()
      Returns the number of threads created by this factory.
      Returns:
      the total count of threads created

    • getNamePrefix

      public String getNamePrefix()
      Returns the name prefix used for thread naming.
      Returns:
      the name prefix

    • isDaemon

      public boolean isDaemon()
      Returns whether this factory creates daemon threads.
      Returns:
      true if daemon threads are created

    • toString

      public String toString()
      Overrides:
      toString in class Object