Quasar

Quasar is a library that provides high-performance lightweight threads, Go-like channels, Erlang-like actors, and other asynchronous programming tools for Java and Kotlin. Quasar is developed by Parallel Universe and released as free software, dual-licensed under the Eclipse Public License and the GNU Lesser General Public License. Quasar fibers rely on bytecode instrumentation. This can be done at classloading time via a Java Agent, or at compilation time with an Ant task. Quasar’s lightweight thread implementation relies on bytecode instrumentation. Instrumentation can be performed at compilation time or at runtime using a Java agent. The easy and preferable way to instrument programs using Quasar is with the Java agent, which instruments code at runtime. Sometimes, however, running a Java agent is not an option. Quasar supports AOT instrumentation with an Ant task.