20 years ago there was no interview. i passed exam. no sjt test at that time. now it requires exam. aptitude test. and interview. there are huge prep private institutes available similar to college classs. 1 to 100 competition ratio to be selected for actual service. not worth to invest if u are creative. well managed. people apply for it for life pension. 2000 grant monthly after 30 yrs service from age of 60. now law is changing to 65