Exactly same time is not possible. Java Virtual Machines often use the underlying scheduler provided by the OS kernel. Scheduler implements a function s(t) from time to processes that assigns the CPU to a process according to a specific policy (FIFO, SJF, Round Robin, Real Time policies, and so on). In each t, only one process is currently running, others are put in the ready queue unless the dispatcher performs a context switch.
solved Java concurrently overwrite a primitive with the same value