Call for Discussion: New Project: Leyden

Mohammed Al-Moayed mohammed.moayed at
Thu Jun 4 16:27:14 UTC 2020

Please, consider me, to participate in this project 


> On Apr 27, 2020, at 7:40 PM, mark.reinhold at wrote:
> I hereby invite discussion of a new Project, Leyden, whose primary goal
> will be to address the long-term pain points of Java’s slow startup time,
> slow time to peak performance, and large footprint.
> Leyden will address these pain points by introducing a concept of _static
> images_ to the Java Platform, and to the JDK.
>  - A static image is a standalone program, derived from an application,
>    which runs that application -- and no other.
>  - A static image is a closed world: It cannot load classes from outside
>    the image, nor can it spin new bytecodes at run time.
> These two constraints enable build-time analyses that can remove unused
> classes and identify class initializers which can be run at build time,
> thereby reducing both the size of the image and its startup time.  These
> constraints also enable aggressive ahead-of-time compilation, thereby
> reducing the image’s time to peak performance.
> Static images are not for everyone, due to the closed-world constraint,
> nor are they for every type of application.  They often require manual
> configuration in order to achieve the best results.  We do, however,
> expect the results to be worthwhile in important deployment scenarios
> such as small embedded devices and the cloud.
> Project Leyden will take inspiration from past efforts to explore this
> space, including the GNU Compiler for Java [1] and the Native Image
> feature of GraalVM [2].  Leyden will add static images to the Java
> Platform Specification, and we expect that GraalVM will evolve to
> implement that Specification.  Developers who use only the standard,
> specified static-image feature will then be able to switch with ease
> between Leyden (in the JDK), Native Image (in GraalVM), and whatever
> other conforming implementations may arise, choosing amongst tradeoffs
> of compile time, startup time, and image size.
> We do not intend to implement Leyden by merging the Native Image code
> from GraalVM into the JDK.  Leyden will, rather, be based upon existing
> components in the JDK such as the HotSpot JVM, the `jaotc` ahead-of-time
> compiler [3], application class-data sharing [4], and the `jlink` linking
> tool [5].
> I propose to lead this Project with an initial set of Reviewers that
> includes, but is not limited to, Alex Buckley, Bob Vandette, Claes
> Redestad, Igor Veresov, Ioi Lam, Mandy Chung, and Vladimir Kozlov.
> This Project will start with a clone of the current JDK main-line
> release, JDK 15, and track main-line releases going forward.  We expect
> to deliver Leyden over time, in a series of JEPs that will likely span
> multiple feature releases.
> Comments?
> - Mark
> [1]
> [2]
> [3]
> [4]
> [5]

More information about the discuss mailing list