Abstract The following report deals with OJB - Object Relational Bridge - as an object relational mapping tool in the J2EE environment. It takes the usage and features into consideration provided by OJB. Besides the concepts and APIs that lays behind that layer, a deeper look into the used APIs, PersistenceBroker, JDO – Java Data Objects - and ODMG – Object Data Management Group – to persist objects are presented. Furthermore, a deeper look into performance differences, advantages and disadvantages is made. Finally, the report ends in the introduction of EJB – Enterprise Java Beans - with regard to the cooperation of OJB and EJB and a detailed description of the deployment and usage of OJB in EJB based applications. Within a two-tier architecture OJB is situated between the client application, where the client sends the requests and the database layer that can consist of different components. The OJB layer includes different features and APIs that will be explained in more detail in the following report.
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