Java has a mechanism called inter-thread communication that allows another thread to enter (or lock) a paused thread’s critical section so that it can be executed.<\/p>\n\n\n\n
Polling<\/strong> is the process of repeatedly testing a condition until it holds true. Loops are frequently used to implement polling in order to determine whether a specific condition is true or false. If it is real, a particular thing happens. Due to this, the implementation uses up a lot of CPU cycles inefficiently.<\/p>\n\n\n\n Java uses the wait()<\/strong>, notify()<\/strong>, and notifyAll()<\/strong> methods to avoid polling. All of these methods are final members of the object class, making them available to all classes. They can only be used inside a synchronized block.<\/p>\n\n\n\n Let’s examine the key distinctions between the wait and sleep methods.<\/p>\n\n\n\n In the event that the flag reads false, Thread2 will wait for the object until it is notified by a notify() method.<\/p>\n\n\n\n When the data production is finished, Thread1 will immediately notify Thread2 that data is available for receipt. Thread1 and Thread2 effectively communicate with one another in this way.<\/p>\n\n\n\n Note: also read about<\/em>\u00a0the\u00a0Synchronization in Java<\/a><\/p>\n\n\n\n If you like my post, please follow me to read my latest post on programming and technology.<\/p>\n\n\n\nJava multi-threading approach to prevent\u00a0this issue:<\/h5>\n\n\n\n
Difference between wait and sleep<\/h5>\n\n\n\n
wait()<\/th> sleep()<\/th><\/tr> The lock is released by the wait() method.<\/td> The lock is not released by the sleep() method.<\/td><\/tr> It is a method of the class Object.<\/td> It is a thread class method.<\/td><\/tr> Furthermore, it is the non-static method<\/td> It is the static method<\/td><\/tr> It should be notified by notify() or notifyAll() methods<\/td> After the specified amount of time, sleep is completed.<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n Example<\/h5>\n\n\n\n
\/\/In this program, we will understand how to use wait and notify.\n\/\/ It is the most efficient way for thread communication.\npublic class A \n{\n int i;\t\n boolean flag = false; \/\/ flag will be true when data production is over.\nsynchronized void deliver(int i)\n{\n if(flag)\n try\n {\n wait(); \/\/ Wait till a notification is received from Thread2. There will be no wastage of time.\t \n }\n catch(InterruptedException ie)\n {\n System.out.println(ie);\t \n }\n this.i = i;\t\n flag = true; \/\/ When data production is over, it will store true into flag.\n System.out.println(\"Data Delivered: \" +i);\n notify(); \/\/ When data production is over, it will notify Thread2 to use it.\n }\nsynchronized int receive()\n{\nif(!flag)\ntry {\n wait(); \/\/ Wait till a notification is received from Thread1.\t\n}\ncatch(InterruptedException ie){\n System.out.println(ie);\t\n}\n System.out.println(\"Data Received: \" + I); \n flag = false; \/\/ It will store false into flag when data is received.\n notify(); \/\/ When data received is over, it will notify Thread1 to produce next data.\n return i;\n }\n}\npublic class Thread1 extends Thread\n{\n A obj;\n Thread1(A obj)\n {\n this.obj = obj;\n }\npublic void run()\n{\nfor(int j = 1; j <= 5; j++){\n obj.deliver(j); \t\n }\n}}\npublic class Thread2 extends Thread \n{\nA obj;\nThread2(A obj)\n{\n this.obj = obj;\n}\npublic void run()\n{\nfor(int k = 0; k <= 5; k++){\n obj.receive();\t\n}\n }}\npublic class Communication \n{\npublic static void main(String[] args) \n{\n A obj = new A(); \/\/ Creating an object of class A.\n\n\/\/ Creating two thread objects and pass reference variable obj as parameter to Thread1 and Thread2.\nThread1 t1 = new Thread1(obj);\nThread2 t2 = new Thread2(obj);\n\/\/ Run both threads.\n t1.start();\n t2.start();\n }\n}<\/code><\/pre>\n\n\n\nOutput<\/h5>\n\n\n\n
Data Delivered: 1\n Data Received: 1\n Data Delivered: 2\n Data Received: 2\n Data Delivered: 3\n Data Received: 3\n Data Delivered: 4\n Data Received: 4\n Data Delivered: 5\n Data Received: 5<\/code><\/pre>\n\n\n\nFollow Me<\/strong><\/h5>\n\n\n\n