Your class VoxLineOfService is a JPA entity. Instances of this class can be stored to and retrieved from a database using JPA (the
Java Persistence API). The source code you posted of class VoxLineOfService is incomplete and will not compile, because some of the methods are using member variables that are not declared anywhere in the class. The methods unlinkLineOfService, reasignLineOfService and export are using member variables: endUser, billPayer, custodian and owner that are not declared in the class. You'll get compiler errors when you would try to compile this.
Your class LineOfServiceBean is just a regular Java class (a POJO = Plain Old Java Object), that seems to have the same fields as VoxLineOfService.
Probably somewhere in your system, objects of type VoxLineOfService are converted into objects of type LineOfServiceBean. Maybe, somewhere in that code, the original programmer forgot to set some fields, such as the enduser field in LineOfServiceBean.
It's really hard to debug a system with so much code through the forum.
I would use an
IDE to automatically find all the places where a LineOfServiceBean is created, and investigate there how those objects are being initialized and where they go.