It will depend on the version of Eclipse, and the weblogic plugin (OEPE) you are using. Without the correct connectors Eclipse is only aware that WebLogic server can run JPA1.0. Perhaps try the latest version of OEPE pack here and point it at your workspace.
You also need to make sure the version of WebLogic you are using supports JPA2- you have tagged the question as weblogic 10.x which only supports JPA2.0 in 10.3.4 and later, and may require you to patch weblogic to enable the support.