Hello Prashant, 

JNU has a total of 23 seats for MA in German. 8 seats are for German literature students and the rest 15 for translation students. 

A general overview of what they require to know in the entrance exam I.e syllabus is: 

1. Candidates are required to have sufficient knowledge of the German language equivalent to Oberstufe. 

2. Need to have basic idea of the civilization and culture of German speaking candidates

3. You need to possess knowledge equivalent to completing a B.A in history of German literature. 

4. The ability to linguistically analyze and translate German texts to English. 

There is no definite amount of candidates. It is very variable. Therefore it is not possible to give you an exact number. 

There is no specific book for MA in German but people prepare referring to compilations of previous year papers. It will give you sufficient idea regarding the kind of preparation you need and this is a common way of preparing for the entrance test. You can download the papers for MA in German here: https://www.shiksha.com/university/jnu-jawaharlal-nehru-university/jnuee-exam-question-papers?course=849

Hope this helps :)