This option causes the JIT compiler to run with a subset of optimizations, which can improve the performance of short-running applications.

Note: For compatibility with other Java™ virtual machines, you can also specify the -client option, which results in identical behavior to -Xquickstart.



Default behavior

By default, -Xquickstart is disabled.


The JIT compiler is tuned for long-running applications typically used on a server. When you specify this option, the compiler uses a subset of optimizations, which results in faster compilation times that improve startup time. However, longer running applications might run more slowly, especially applications that contain hot methods and other methods using a large amount of processing resource.

When the AOT compiler is active (both shared classes and AOT compilation enabled), -Xquickstart causes all methods to be AOT compiled. The AOT compilation improves the startup time of subsequent runs, but might reduce performance for longer running applications, especially those that contain hot methods.

Note: The implementation of -Xquickstart is subject to change in future releases.