Pessimistic Lock

Developers can use pessimistic locking but they will need to define the lock manager using EntityManager's lock() or find() methods.

当然，开发者也可以自行使用悲观锁（pessimistic locking），但他们需要使用EntityManager的lock（）或者find（）方法来定义锁管理器。

This is weaker than a pessimistic session lock& the convention adhered to by the participants is to warn, not to block.

它较悲观会话锁更弱一些，相关方约定发出警告，而不是阻止。

Of course this also leads to the same issues such as questions about optimistic versus pessimistic locking, lock granularity, and the performance impact.

然而这也带来了和数据库事务同样的问题，比如乐观锁还是悲观锁，锁的粒度以及对性能的影响。

A standardardized pessimistic lock manager.

一个标准化的悲观锁（pessimistic lock）管理器。