BLOCKED - this state represents a thread which has been blocked and is waiting for a moniotor to enter/re-enter a synchronized block/method. A thread gets into this state after calling Object.wait method.
WAITING - this state represnts a thread in the waiting state and this wait is over only when some other thread performs some appropriate action. A thread can get into this state either by calling - Object.wait (without timeout), Thread.join (without timeout), or LockSupport.park methods.

BLOCKED是指線程正在等待獲取鎖；WAITING是指線程正在等待其他線程發(fā)來的通知（notify），收到通知后，可能會(huì)順序向后執(zhí)行（RUNNABLE），也可能會(huì)再次獲取鎖，進(jìn)而被阻塞住（BLOCKED）。

PS:
notify與notifyAll的區(qū)別
notify是將某個(gè)waiting的線程狀態(tài)改變?yōu)閎locked(由于notify的線程尚未退出臨界區(qū)，尚未釋放鎖，所以被喚醒的線程狀態(tài)變?yōu)閎locked)，notifyAll是將所有線程的狀態(tài)改變?yōu)閎locked。