What is the effect of these defects in the trial?

m leaving a very short reply to ur queries; for query no. 1 and 2 read S.311 Cr.P.C

and for query no. 3 in my opinion yes this point can be raised in appeal too, if the court does a technical error then the party shall not suffer........mere use of word exhibit will not prove a document, it has to be proved as according to law.....its a duty of the court to rely upon well corroborated or well proved evidence only.

In addition to Kiran's answer to question 3: Exhibit as per Section 4 of the Court fees Act, means a document exhibited for the purpose of being taken into consideration in deciding some questions or other in respect of the proceedings in which it is filled.Once the documents is exhibited in the court of first instance and if it is not agitated in the court of first instance no question of challenging the same in the appellate court arise.

1. Trial would not vitiated merely because prosecution failed to examine important witnesses.

2. No. after closure of defence witness prosecution cannot  summon witness as it would be considered as filling in the lacunae.

3. i agree with kirn sir.

Non production of material witnesses amounts to acquittal as per held by various high courts

Once a document is exhibited, its admissibility can not be challenged in later stages, not in appeal too, except when serious question of law arises or a legal issue is involved.

 after closing of defence witness, no other prosecution witnesses may be recalled