Eclipse LSP4J is a Java implementation of VSCode's language server protocol intended to be consumed by tools and language servers implemented in Java.
Eclipse Buildship is a collection of Eclipse plug-ins that provide support for building software using Gradle.
Buildship aims to provide a deep integration of Gradle into Eclipse. Buildship also aims to make the Eclipse IDE more powerful by allowing the user to do more from within the IDE.
Buildship 1.0 is targeted towards Gradle users. Later versions will target Gradle build masters.
The release announcements are available on the Buildship forum.
Eclipse Xtext is a framework for development of programming languages and domain specific languages. It covers all aspects of a complete language infrastructure, from parsers, over linker, compiler or interpreter to fully-blown top-notch Eclipse IDE integration. It comes with good defaults for all these aspects and at the same time every single aspect can be tailored to your needs.