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OpenSAML 4, the current Java library version, is based on Java 11, and supports SAML 1.0, 1.1, and 2.0. Additionally, various development groups have found the framework created to support OpenSAML useful for their own work and the Java codebase includes some code supporting WS-Addressing, WS-Security, WS-Trust and XACML.
The previous major version based on Java 8 is now End of Life and no longer supported.
The OpenSAML libraries do not provide a complete SAML identity or service provider. If you are looking for such software you should check out the Shibboleth project instead. Also, these libraries will not teach you any of the specifications listed above. The libraries are meant solely to support individuals who have taken the time to read and understand the specifications and are not in general a good solution for those looking for a quick way to implement SAML.
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