This paper is about Java object relational frameworks and related processes. The goal of this work consists of showing design patterns for ORM, introducing Java ORM standards along with the main implementations, finding criteria for comparison of ORM frameworks and showing working ORM example in a case study. This paper has the following structure: The first part of this paper discusses main ORM design patters, approaches to ORM and performance related features of Java ORM frameworks. Next part describes available Java ORM standards and implementations and introduces case study attached to this part as appendix. The last part of this paper presents ORM frameworks comparison criteria and compares main implementations of the JPA standard.