As an open-source project, contributions of any kind are very welcome to Apache WSS4J.
To report a bug or request a new feature, please file a JIRA ticket. If you do not have an account for the Apache JIRA instance, then you will need to request one first via the mailing lists. Before filing a JIRA ticket, please discuss the issue on the dev or user mailing list to make sure that the issue is valid. Please also search for the open issues in the project, or issues that are fixed but not yet released, to make sure the issue hasn't been reported before.
Code contributions should be done as pull requests on the Apache WSS4J GitHub repo. Before contributing any code, please run "mvn clean install" in the root directory and ensure that all the CheckStyle and PMD checks pass, as well as all of the unit tests. Ideally any bug fix and new feature should have unit tests submitted as part of the pull request.