GlassFish HK2

HK2 (Hundred-Kilobyte Kernel) is a light-weight and dynamic dependency injection framework and is a part of the GlassFish Application Server.

HK2
Developer(s)	Eclipse Foundation
Stable release	3.1.1 / July 4, 2024; 12 months ago (2024-07-04)
Repository	github.com/eclipse-ee4j/glassfish-hk2
Operating system	Cross-platform
Available in	Java 6 or Higher
Type	Dependency Injection Kernel
License	Eclipse Public License 2.0 or GPL v2 w/Classpath exception
Website	eclipse-ee4j.github.io/glassfish-hk2/

HK2 complies with JSR 330 (Dependency Injection for Java). It has useful utilities for marking classes as services and interfaces as contracts.^[1]

Some of the features of HK2 DI Kernel are

• Custom scopes
• use of proxies
• Custom injection resolution
• Assisted injection
• J-I-T injection resolution
• Custom validation and security
• Run Level Services^[1]