服务器开发资料； 这是一个面向对象数据库，性能不错的说，最大优点可以免费使用，不像db40需付费。适合做持久层管理，手机网络游戏和应用-Development of information server this is an object-oriented database, performance, good that the biggest advantage of free access, unlike Pay db40. Suitable for persistence layer

DataNucleus provides Java data persistence and management platform allowing federation of data as well as JDO, JPA and web services interfaces. It supports heterogeneous datastores (RDBMS, db4o, LDAP, Excel, XML, NeoDatis, JSON, ODF, BigTable, HBase)