Eclipse Collections is a comprehensive collections library for Java. The
library enables productivity and performance by delivering an expressive and
efficient set of APIs and types. The iteration protocol was inspired by the
Smalltalk collection framework, and the collections are compatible with the
Java Collection Framework types.

Eclipse Collections is compatible with Java 8+. Eclipse Collections is a part
of the OpenJDK Quality Outreach program, and it is validated for different
versions of the OpenJDK.