Java will handle that for you. In java, the garbage collector runs periodically looking for chunks of memory that nothing has a reference to anymore. When it finds one, the garbage collector frees up that memory.
Once we replace the original options variable with a new one, we no longer have a reference to that first piece of memory and it will be automatically cleaned up.
Assigning it to null won’t make a significant difference over freeing up references to the object. Manually setting variables to null is going to complicate your code without adding any benefit.