1. You may go thru the appointment letter, HR policy, service rules and regulations, standing orders etc...........................................
Most likely your employer shall not approve of it, if you join without consent and prior information.
2.The shift timing can be changed anytime by the company.
In that case you shall loose on attendance and fee paid by you.
If you join after having approval in writing then employer may not change shift timings.
Some companies have a policy to promote qualification of its employees and even reimburse fee.
If the criteria of the employer demands signing of some BOND for it then you may avoid and must not sign without consulting elders in the family and your lawyer. Sometimes the conditions set by company are too harsh.