GlassFish HK2

{{Infobox software

| name = HK2

| logo =

| screenshot =

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| developer = Eclipse Foundation

| released =

| latest release version = 3.1.1

| latest release date = {{start date and age|2024|07|04}}

| latest preview version =

| latest preview date =

| operating system = Cross-platform

| language = Java 6 or Higher

| genre = Dependency Injection Kernel

| license = Eclipse Public License 2.0 or GPL v2 w/Classpath exception

}}

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

HK2 complies with JSR 330 (Dependency Injection for Java). It has useful utilities for marking classes as services and interfaces as contracts.{{cite web |url=https://javaee.github.io/hk2/ |title=HK2 - Dependency Injection Kernel |website=javaee.github.io |language=en |access-date=2017-11-19}}

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