multithreading - When a process or thread gets blocked, does it wait forever for a notification or just sleep for a while? -

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i stumbled question when reading “jvms typically implement blocking suspending blocked thread , rescheduling later” http://www.ibm.com/developerworks/java/library/j-jtp04186/?s_tact=105agx52&s_cmp=cn-a-j

when process or thread gets blocked when doing io operations (read, write) or getting access exclusive resource (lock, synchronized), when re-execute? waiting until getting notification somewhere or quit turn , run again after while?

has specified platform? os or jvm?

that devolve underlying os must provide threading support vm - has way java app can co-exist harmoniously other proceses , threads typically loaded on os - browsers, sidebars, anitvirus, video/audio players, torrent clients, os internal threads etc. etc.

the code of blocked thread gets no cpu cycles @ all. thread in state unused-for-now stack allocation , struct/class pointer in container in kernel, waiting else change state. if remains blocked or extended time, stack may swapped out on busy system.

so yes, waiting until getting notification somewhere.


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