Stars
The java implementation of Apache Dubbo. An RPC and microservice framework.
Apache Druid: a high performance real-time analytics database.
JSqlParser parses an SQL statement and translate it into a hierarchy of Java classes. The generated hierarchy can be navigated using the Visitor Pattern
CrateDB is a distributed and scalable SQL database for storing and analyzing massive amounts of data in near real-time, even with complex queries. It is PostgreSQL-compatible, and based on Lucene.
Security engine for Java (authentication, authorization, multi frameworks): OpenID Connect, SAML2, CAS, OAuth, LDAP, JWT...
A java HttpServletRequestWrapper to guard against sql injection and xss attacks