What is the difference between cascade and orphan removal from DB?

[ @OneToMany(cascade=REMOVE, mappedBy="customer")
public List<Order> getOrders() { ... }

and

@OneToMany(mappedBy="customer", orphanRemoval="true")
public List<Order> getOrders() { ... } ]

Solution: 

  CascadeType.REMOVE indicates that remove operations should be
  cascaded automatically to entity objects that are referenced by that
  field of other entity.  

@Entity
class Employee {
     :
    @OneToOne(cascade=CascadeType.REMOVE)
    private Address address;
     :
}

Orphan Removal
JPA 2 supports an additional and more aggressive remove cascading mode which can be specified using the orphanRemoval element of the @OneToOne and @OneToMany annotations:
 
@Entity class Employee {
   
 @OneToOne(orphanRemoval=true) 
 private Address address;  

 }