Status message

This proposal has been approved and the Eclipse LSP4J project has been created.

Eclipse LSP4J

This proposal is in the Project Proposal Phase (as defined in the Eclipse Development Process) and is written to declare its intent and scope. We solicit additional participation and input from the community. Please login and add your feedback in the comments section.
Parent Project: 

The Language Server Protocol currently defined by the VSCode team at [1] is an effort to unify communication between editors (tools) and advanced language tooling.

[1] - https://github.com/Microsoft/language-server-protocol


This project aims at providing a reusable Java implementation of VSCode's language server protocol. It implements the types as well as the communication, including serialization to and deserialization from JSON.


LSP4J is a Java implementation of VSCode's language server protocol intended to be consumed by tools and language servers implemented in Java.

Why Here?: 

The Eclipse Foundation is a trusted open source foundation and hosts a number of potential clients of this project, such as (Eclipse Platform, JDT, Xtext, JSDT, etc.)

Project Scheduling: 

We intend to provide a first incubation release shortly after project creation.

Future Work: 

It is planned to keep up with the evolution of the language server protocol.

Interested Parties: 
Source Code
Initial Contribution: 

The initial contribution is currently hosted at https://github.com/TypeFox/ls-api.

Source Repository Type: 
Max Rydahl Andersen's picture

The proposal says "LSP4J is a Java implementation of VSCode's language server protocol i" but https://github.com/TypeFox/ls-api is using XTend.

Is the plan to make this pure java ?


And we've taken a quite simpler approach afaics with the java languager server that uses json schemas which we hope to be adopted by the spec eventually.

Would this project be interesting adopting that approach ?

Sven Efftinge's picture

Hi Max,

yes to both.

See https://github.com/TypeFox/ls-api/issues/28 (although xtend generates java, so ls-api already is java)

Regarding the json. We are waiting fro MS to accept the according PR. But then we plan to generate the type defs from that.

Mickael Istria's picture

Red Hat is definitely interested in this project and would like to be listed as interested parties.

Sven Efftinge's picture

Thank you Mickael! I added you.

Rafael Chaves's picture

Looking forward to seeing LSP4J as an Eclipse project. We are planning to adopt it in Cloudfier, and we hope Orion too will provide support for the Language Server Protocol as well.

Sven Efftinge's picture

Good to know! I've heard rumors of Orion going to support it, too.

Mickael Istria's picture

It's much more than rumors: here is some experimental and encouraging progress: https://www.youtube.com/watch?v=A-jnqySRA50 . However, as it's not Java, I don't think Orion is directly interested in the LSP4J project. That said, I guess they'd be glad to share ideas/plans/work if you ask on their mailing-list.

Karsten Thoms's picture

itemis is highly interested to support this project