jpa project problem in hibernate console configuration

when i create a jpa project under eclipse, i encoutered the following problem: when i create the a configuration file, i check creat console, next when i specify jpa as type in the main tab of the Console Configuration Wizard, i get the error message in the top of the wizard:

how can i resolve this problem?开发者_StackOverflow

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I think you should create Persistence unit first check this link http://schuchert.wikispaces.com/JPA+Tutorial+1+-+Persistence+Unit