what's the difference between PvmExecution,Execution and DelegateExecution'

[ken2000]

Hi,everyone,
  i don't qiute understand what's the difference between PvmExecution,Execution and DelegateExecution，what's the relationship between them?
   someone can tell me ? thanks!

[trademak]

It's basically abstraction. DelegatExecution just hides the dirty details from the user. PvmExecution is a class at the core of the Activiti Engine, which is not exposed directly. ExecutionEntity is one of the main classes in the Activiti Engine, and a lot of the Engine functionality is implemented in that class.

Best regards,