JSX serializes Java objects to XML. You can persist objects, evolve them, and send them over the network and between applications. Your object data becomes human-readable and human-writable. You can test it, search it, profile it, audit it, and edit it with ordinary text and XML tools. JSX handles all POJOs and also all classes that require Java's own object serialization.
DataNucleus AccessPlatform is a standards-compliant Java persistence product. It is fully compliant with the JDO1, JDO2, JDO2.1, JDO2.2, JDO3, JPA1, JPA2 and JPA2.1 Java standards, and provides a REST API. It complies with the OGC Simple Feature Spec for persistence of geospatial Java types. It allows access to all popular RDBMS available today, together with the MongoDB, LDAP, NeoDatis, JSON, Excel/ODF spreadsheets, XML, BigTable, HBase, and Neo4j databases.
SymmetricDS provides file and database synchronization with support for multi-master replication, filtered synchronization, and transformation across the network in a heterogeneous environment. It supports multiple subscribers with one-direction or bi-directional, asynchronous data replication. It uses Web and database technologies to replicate data as a scheduled or near-realtime operation. The software has been designed to scale for a large number of nodes, work across low-bandwidth connections, and withstand periods of network outage. It works with most operating systems, file systems, and databases, including Oracle, MySQL, MariaDB, PostgreSQL, MS SQL Server (including Azure), IBM DB2, H2, HSQLDB, Derby, Firebird, Interbase, Informix, Greenplum, SQLite (including Android), Sybase ASE, and Sybase ASA (SQL Anywhere) databases.
Vibur DBCP is a concurrent, fast, and fully-featured JDBC connection pool based on Java dynamic proxies. It supports a fairness parameter, statement caching, Hibernate integration, and SQL queries logging, among other features. Various configuration examples (with Spring, Hibernate, etc.) are provided.
BaseX is a light-weight, high-performance, and scalable XML database system and XPath/XQuery processor, including full support for the W3C Update and Full Text extensions. An interactive and user-friendly GUI frontend gives you great insight into large XML data instances. It is platform independent and works out of the box.
PGObject::Simple::Role provides an interface to the PGObject service locator for Moo and Moose Perl classes. This service locator is intended to integrate Perl objects with PostgreSQL user-defined functions, and this uses the "simple" mapping approach. Between PGObject::Simple::Rrole and PGObject::Util::DBMethod, it is possible to write fully-declarative classes in which all calculation logic is handed off to database functions.
hamsterdb Embedded Storage is an embedded database engine written in ANSI-C. It includes B+Trees with variable length keys and records. It supports in-memory databases and endian-independent files, database cursors, multiple databases in one file, "record number" databases, and duplicate keys. hamsterdb is very fast and highly configurable. It compiles and runs on Unix platforms, Linux, Microsoft Windows, and Windows CE.
OrientDB is a NoSQL DBMS which can store 150,000 documents per second on common hardware. Even with a document-based database, the relationships are managed as in graph databases, with direct connections among records. You can traverse entire or parts of trees and graphs of records in a few milliseconds. It supports schema-less, schema-full, and schema-mixed modes, has a strong security profiling system based on users and roles, and supports SQL between the query languages. Thanks to the SQL layer, it's straightforward to use for people skilled in the relational world.