Eclipse不会初始化JPA持久性 [英] Eclipse doesn't initialize JPA persistence

问题描述

当我尝试运行JPA项目时，出现以下错误消息:

when I try to run a JPA project, I get the following error message :

Exception in thread "main" java.lang.ExceptionInInitializerError
    at org.eclipse.persistence.internal.jpa.EntityManagerFactoryProvider.<clinit>(EntityManagerFactoryProvider.java:55)
    at org.eclipse.persistence.jpa.PersistenceProvider.createEntityManagerFactoryImpl(PersistenceProvider.java:92)
    at org.eclipse.persistence.jpa.PersistenceProvider.createEntityManagerFactory(PersistenceProvider.java:188)
    at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:79)
    at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:54)
    at dao.LayerDAO.<init>(LayerDAO.java:10)
    at exec.Run.main(Run.java:9)
Caused by: java.lang.NullPointerException
    at org.eclipse.persistence.platform.server.NoServerPlatformDetector.checkPlatform(NoServerPlatformDetector.java:28)
    at org.eclipse.persistence.platform.server.ServerPlatformUtils.detectServerPlatform(ServerPlatformUtils.java:58)
    at org.eclipse.persistence.internal.jpa.IsolatedHashMap.<clinit>(IsolatedHashMap.java:48)
    ... 7 more

该项目以前运行过，但是由于问题我需要重新安装Glassfish，现在它已损坏. 我尝试创建一个新项目，但收到了相同的错误消息.

This project was running before, but I needed to reinstall Glassfish because of problems and now it's broken. I tried to create a new project but I got the same error messages.

您有什么想法可以解释这种行为吗?

Do you have an idea of what could explain such a behavior ?

感谢

推荐答案

感谢@Gimby，他让我验证了EclipseLink版本，因此我必须进入项目属性. 在查看BuildPath参数之后，我尝试查看我选择的目标运行时"，发现没有选择任何目标. 既然我已经检查过，一切都会变得更好.

Thanx to @Gimby who made me verified my EclipseLink version, I had to go into the project properties. After a look in the BuildPath parameters, I tried to look at the "targeted runtime" I've chosen and found that none was selected. Since I've checked it, everything goes better.

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