This was just a simple example of one way that you can use the .NET Threading syntax which happened to use a static method. If you need to use an instance method with threading you can do this as follows:
$set ilusing"System"
$set ilusing"System.Threading"
program-id. Program1 as "testthreading.Program1".
data division.
working-storage section.
01 any-key pic x.
procedure division.
declare thread1 as type Thread
declare myobject as type ThreadWork = new ThreadWork
declare threadDelegate as type ThreadStart = new ThreadStart(myobject::DoWork)
set thread1 to new Thread(threadDelegate)
invoke thread1::Start
perform varying i as binary-long from 0 by 1 until i > 3
display "In Main"
invoke type Thread::Sleep(100)
end-perform
accept any-key
goback.
end program Program1.
class-id ThreadWork.
working-storage section.
method-id DoWork public.
procedure division.
perform varying i as binary-long from 0 by 1 until i > 3
display "Working Thread..."
invoke type Thread::Sleep(100)
end-perform
goback.
end method.
end class.
If you do wish to use a static method that does file handling then the file itself should be defined as static or you will get errors.
Example:
class-id ThreadWork.
select optional test-file assign to "testfile.dat"
organization is line sequential
file status is file-status.
file section.
fd test-file static.
01 test-record pic x(20).
working-storage section.
01 file-status pic x(2) static.
method-id DoWork static.
procedure division.
open extend test-file
display "open = " file-status
perform varying i as binary-long from 0 by 1 until i > 3
display "Working Thread..."
move i to test-record
write test-record
invoke type Thread::Sleep(100)
end-perform
close test-file
goback.
end method.
end class.