I want to implement following in java code :

Main thread 1. create three threads 2. wait for completion of stage 2 of all three threads

1. access all three local variable (LC0, LC1, LC2) of threads
2. bulid a new main data (MD)

3. resume all three threads execution

4. wait for end of each thread

5. access all three local variable (LC'0, LC'1, LC'2)

   Each threads executes following

   1. build a local variable (LC)
      

   2. wait till main thread signals

   3. access a main data (MD)

   4. update local data (LC'= updated LC)
   5. do something with local data (LC')
   6. end

My problems:

1. There is no need of synchronization. hence i can't use wait and notify.

2. How to access local data of threads in the when threads is paused ( is waiting).

3. How to resume execution of all three threads.

I will expain the algorithm if required.
Please help me.