Java 多线程 英文.ppt

Each object has just one lock. A class can have both synchronized and non-synchronized methods If one thread enter the synchronized method, it means it get the object lock, other threads can’t go to any synchronized method, but can enter to non-synchronized methods The synchronized static method will get the class lock, non-static synchronized method will get the object instance lock. If a thread goes to sleep, all locks which it has will not be released, but wait() method will release the lock A thread can acquire the lock more than once NEW state After the creations of Thread instance the thread is in this state but before the start() method invocation. At this point, the thread is considered not alive. RUNNABLE state A thread first enters runnable state after the invoking of start() method On this state a thread is waiting for a turn on the processor. Running state A thread is in running state that means the thread currently executing. There are several ways to enter in Runnable state but there is only one way to enter in running state: the scheduler select a thread from runnable pool. BLOCKED state Thread state for a thread blocked waiting for a monitor lock. A thread in the blocked state is waiting for a monitor lock to enter a synchronized block/method? WAITING states Thread state for a waiting thread. A thread is in the waiting state due to calling one of the following methods: Object.wait?with no timeout Thread.join?with no timeout A thread in the waiting state is waiting for another thread to perform a particular action. For Example: Object.notify()?or?Object.notifyAll() for Object.wait Thread to terminate for Thread.join TIMED_WAITING states Thread state for a waiting thread with a specified waiting time due to calling one of the following methods? Thread.sleep Object.wait?with timeout Thread.join?with timeout TERMINATED states The thread has completed execution. Deadlock?describes a situation where two or more threads are blocked forever, waiting