How do I implement CFG to CNF in java?

In this project, read a CFG from a txt file, simplify it by removing ε-rules and useless rules,
and print out the simplified equivalent CFG. No need to care or remove unit-rules.
For example, given the following CFG in a txt file (0 denotes empty string and "-" denotes arrow head "→"):
S-aA|aBB
A-aaA|0
B-bB|bbC
C-B
After processing, your program should print out the following simplified equivalent CFG:
S-aA|a
A-aaA|aa
The following are a few more examples you can use to test your program (I highly recommend that you come up
with more examples to make sure the correctness of your program):
(1) S-AaBaCbD
A-0|a
B-0|b
C-0|c
D-0|d
For the above CFG, the print out should be
S-aab|Aaab|aBab|AaBab|aaCb|AaaCb|aBaCb|AaBaCb|aabD|AaabD|aBabD|AaBabD|aaCbD|AaaCbD|aBaCbD|AaBaCbD
A-a
B-b
C-c
D-d
(2) S-AaB|aaB
A-0
B-baA|0
For the above CFG, the print out should be
S-aB|aaB|a|aa
B-ba
(3) S-ASA|aB
A-B|S
B-b|0
For the above part of the transition table of a NFA, the print out should be
S-ASA|aB|a|SA|AS
A-B|S
B-b
Note that your program must be able to work for any CFG, not only just for the above given examples.

(2) S-AaB|aaB
A-0
B-baA|0
For the above CFG, the print out should be
S-aB|aaB|a|aa
B-ba
(3) S-ASA|aB
A-B|S
B-b|0
For the above part of the transition table of a NFA, the print out should be
S-ASA|aB|a|SA|AS
A-B|S
B-b
Note that your program must be able to work for any CFG, not only just for the above given examples.