| --- |
| layout: default_md |
| title: Virtual Threads |
| title-class: page-title-classic |
| type: classic |
| --- |
| |
| [Using ActiveMQ](using-activemq-classic-5) > [Configure version 6 Virtual Threads](virtual-threads) |
| |
| ### Virtual Threads support |
| |
| ActiveMQ support for Virtual Threads is in Technology Preview stage. Virtual Thread support is implemented using multi-release jar, so no special changes to the distribution are required. |
| |
| ### Virtual Threads benefits |
| |
| * Performance on-par (or better) than reactive coding approaches |
| * JDK-based option for peak concurrency performance |
| * Automatically scales based on need and detected CPU cores |
| * Less configuration tuning required for administrators |
| * Easier to code extensions |
| * Scales connection count |
| * Scales destination count |
| |
| ### Configuration |
| |
| To enable Virtual Threads in ActiveMQ 6.3.x (and higher) |
| |
| 1. Run Apache ActiveMQ 6.3.0 (or higher) |
| 2. Run with Java JDK 25 (or newer) |
| 3. Edit conf/activemq.xml |
| |
| <broker ... virtualThreadTaskRunner="true" .. > |
| |
| 4. Run ActiveMQ and confirm with the following log message: |
| |
| INFO | VirtualThreadExecutor initialized name:ActiveMQ BrokerService[localhost] Task |
| |
| NOTE: The log message may be removed in the future |
| |
| ### ActiveMQ Virtual Thread Implementation Progress |
| |
| Virtual Thread support was released with ActiveMQ v6.3.0. User feedback is welcome! Please open a GitHub issue with questions and comments. |
| |
| JIRA|Status|Target Version|Completed Version|Feature|Notes |
| ---|---|--- |
| [AMQ-9394](https://issues.apache.org/jira/browse/AMQ-9394) | PR [#1172](https://github.com/apache/activemq/pull/1172) | 6.2.0 | 6.3.0 | Task Runner Factory | Tech Preview support to allow Virtual Thread Executor Service |
| |
| ### Reference: Running with Virtual Threads |
| |
| JDK 25 (or newer) should always be used when running Virtual Threads to avoid thread pinning. |
| |
| Technical factors: |
| |
| * ActiveMQ currently (6.1.x) uses virtual thread-friendly locking for key data structures in the Queue class |
| * ActiveMQ currently (6.1.x) uses virtual thread-unfriendly _synchronized_ code blocks in many areas in the client and broker code |
| * JDK 23 is slated to address the thread pinning in _synchronized_ code blocks |
| * JDK 25 is the next planned LTS release after JDK 21 |
| * Areas of ActiveMQ source code will need to be modernized to be more virtual thread friendly |
| * New virtual-thread first implementations may be added using extension points in the broker, vs refactoring the existing stable components |
| |
| JDK thread pinning improvement: |
| ref: https://mail.openjdk.org/pipermail/loom-dev/2024-May/006632.html |
