This open source SDK is your starting point for developing OAuth 2.0 and OpenID Connect based applications in Java. It is provided under the terms of the Apache 2.0 license.

The implemented standards and drafts are listed in the SDK README.md.

Packages 
Package Description
com.nimbusds.oauth2.sdk
Classes for representing, serialising and parsing core OAuth 2.0 concepts.
com.nimbusds.oauth2.sdk.as
OAuth 2.0 Authorisation Server (AS) classes.
com.nimbusds.oauth2.sdk.assertions
Common SAML 2.0 and JWT bearer assertion classes.
com.nimbusds.oauth2.sdk.assertions.jwt
JWT bearer assertions.
com.nimbusds.oauth2.sdk.assertions.saml2
SAML 2.0 bearer assertions.
com.nimbusds.oauth2.sdk.auth
Implementations of OAuth 2.0 client authentication methods at the Token endpoint.
com.nimbusds.oauth2.sdk.auth.verifier
Client authentication verifier framework.
com.nimbusds.oauth2.sdk.ciba
OpenID Connect Client Initiated Backchannel Authentication (CIBA) Flow - Core 1.0 classes.
com.nimbusds.oauth2.sdk.client
OAuth 2.0 dynamic client registration.
com.nimbusds.oauth2.sdk.device
OAuth 2.0 device authorisation grant classes.
com.nimbusds.oauth2.sdk.dpop
OAuth 2.0 Demonstrating Proof-of-Possession at the Application Layer (DPoP) utilities.
com.nimbusds.oauth2.sdk.http
HTTP message and utility classes.
com.nimbusds.oauth2.sdk.id
Common OAuth 2.0 identifier and identity classes.
com.nimbusds.oauth2.sdk.jarm
JWT Secured Authorization Response Mode for OAuth 2.0 (JARM) utilities.
com.nimbusds.oauth2.sdk.jose
JavaScript Object Signing and Encryption (JOSE) utilities.
com.nimbusds.oauth2.sdk.pkce
Proof Key for Code Exchange (PKCE) classes.
com.nimbusds.oauth2.sdk.token
OAuth 2.0 access and refresh token implementations.
com.nimbusds.oauth2.sdk.util
Common utility classes.
com.nimbusds.oauth2.sdk.util.date
Date / time utilities.
com.nimbusds.oauth2.sdk.util.tls
TLS / SSL utilities.
com.nimbusds.openid.connect.sdk
Classes for representing, serialising and parsing core OpenID Connect concepts.
com.nimbusds.openid.connect.sdk.assurance
OpenID Connect for Identity Assurance 1.0 classes.
com.nimbusds.openid.connect.sdk.assurance.claims
Identity assurance claims.
com.nimbusds.openid.connect.sdk.assurance.evidences
Identity evidence classes.
com.nimbusds.openid.connect.sdk.claims
Claims and claim sets used in OpenID Connect.
com.nimbusds.openid.connect.sdk.federation
OpenID Connect Federation 1.0 classes.
com.nimbusds.openid.connect.sdk.federation.api
OpenID Connect Federation 1.0 API classes.
com.nimbusds.openid.connect.sdk.federation.config
OpenID Connect Federation 1.0 entity configuration request and response classes.
com.nimbusds.openid.connect.sdk.federation.entities
OpenID Connect Federation 1.0 entity classes.
com.nimbusds.openid.connect.sdk.federation.policy
OpenID Connect Federation 1.0 policy.
com.nimbusds.openid.connect.sdk.federation.policy.factories
OpenID Connect Federation 1.0 metadata policy factories.
com.nimbusds.openid.connect.sdk.federation.policy.language
Interfaces and classes for the OpenID Connect Federation 1.0 policy language.
com.nimbusds.openid.connect.sdk.federation.policy.operations
OpenID Connect Federation 1.0 policy operations.
com.nimbusds.openid.connect.sdk.federation.registration
OpenID Connect Federation 1.0 explicit client registration.
com.nimbusds.openid.connect.sdk.federation.trust
OpenID Connect Federation 1.0 trust chains and resolution.
com.nimbusds.openid.connect.sdk.federation.trust.constraints
OpenID Connect Federation 1.0 trust chain constraints.
com.nimbusds.openid.connect.sdk.federation.trust.marks
Federation trust marks.
com.nimbusds.openid.connect.sdk.id
Common OpenID Connect identifier and identity classes.
com.nimbusds.openid.connect.sdk.op
OpenID Connect Provider (OP) classes.
com.nimbusds.openid.connect.sdk.rp
OpenID Connect Relying Party (RP) classes.
com.nimbusds.openid.connect.sdk.rp.statement
Software statement processing.
com.nimbusds.openid.connect.sdk.token
OpenID Connect token extensions.
com.nimbusds.openid.connect.sdk.validators
Client-side OpenID Connect ID token, access token and authorisation code validators.
com.nimbusds.secevent.sdk.claims
Security event claims.