From Eclipse Foundation:
Eclipse includes tools made to give developers the freedom of choice in a multi-language, multi-platform, and multi-vendor environment. Eclipse provides a plug-in based framework that makes it easier to create, integrate, and utilize software tools, saving time and money. By collaborating and exploiting core integration technology, tool producers can leverage platform reuse and concentrate on core competencies to create new development technology. The Eclipse Platform is written in the Java language and comes with extensive plug-in construction toolkits and examples.