Which One is optimal to choose ? Syncronized hash map or Hash table with single thread model? How can a hash map syncronized with out using syncrozed blocks in programm?

if i have three programs progA,progB and progC .now i call progB from progA. but the progB does not exist . now i want to call progC instead of starting dump. how can we achieve this.

wat is the difference between array and multiple occurence data structure?

wat is scan and check ? give me real time scenarios where we used these keywords in ur projects?

wat is the difference between dataarea and data queue?

wat is meant by hidden field , why it is used?

i'm working on progA , in that program i want to see the userids of the users who work on this program?