Before we get into thread implementation in Java, let us spend some time and understand the idea and concepts behind threads and concurrent programming.<\/p>\n
Applications are expected to do more than one task at the same time in parallel. Applications which do more than one tasks at a time are called concurrent applications. An example of such concurrent software application is streaming audio application. It must read the digital audio from the network, decompress, manage playback and update the audio simultaneously.<\/p>\n
There are two basic units in the concurrent programming namely Process and Thread. In Java, the concurrent programming is implemented using Threads. Each operating system consists of many processes running to achieve different tasks. Each process has its own memory space. As a matter of fact, JVM (Java Virtual Machine) runs as a single process. A Process contains one more Threads. Each and every Thread which belongs to a Process can share Process\u2019s resources, memory and files.<\/p>\n
Now, we have a good understanding of what is a process and thread. In Java, each thread is an instance of a class Thread. There are two ways to create a thread. The following two sections discuss about these two ways to create and start threads:<\/p>\n
The \u2018Runnable\u2019 interface contains a single method called \u2018run()\u2019 which contains the code to be executed in the thread. Once the thread instance is created and \u2018start()\u2019 method is called on the thread, JVM creates a thread and invokes ‘run()’ method.<\/p>\n
The above snippet of code creates a thread class by implementing \u2018Runnable\u2019 interface and by providing implementation for method \u2018run()\u2019. The \u2018run()\u2019 method will contain the execution logic for the thread to execute. After that, in the main() method we created an instance of the class which implements Runnable interface, and passed that instance to the new Thread object. Finally, we called \u2018start()\u2019 to start the thread execution.<\/p>\n In order to spawn a new thread, we need to call ‘start()’ method. Calling ‘run()’ method directly will execute current thread’s ‘run()’ method. So for this reason we need to call ‘start()’ method. Once the ‘start()’ method is called, JVM creates a new thread instance and executes newly created thread’s ‘run()’ method. Before calling ‘start()’ method on a Thread instance, the thread will be in new<\/i> state. This means that, we only have a Thread object<\/i> not running thread. Once we call ‘start()’ method on the thread instance, the following actions happen:<\/p>\n In fact, every Java program runs in a thread, we can call it the \u2018main\u2019 thread. In the above code example, we instantiated and started a thread from our main thread.<\/p>\n We can also create threads by extending Thread class and by overriding \u2018run()\u2019 method. This is because the Thread class itself implements Runnable interface. The following code sample shows how to create and start a thread by extending Thread class.<\/p>\n As we see the previous code example, we straightaway created our thread instance and started the thread by calling its \u2018start()\u2019 method.<\/p>\n As we already discussed we have two ways to create and start threads in Java. The following two points summarizes these two strategies and discusses which approach is most benefited.<\/p>\n So the recommended way to create threads is by implementing Runnable interface. But, extending Thread class also fine provided that application requirements demands that. In terms of functionality and thread execution, there will not be any difference with respect to the above two approaches.<\/p>\n","protected":false},"excerpt":{"rendered":" Before we get into thread implementation in Java, let us spend some time and understand the idea and concepts behind threads and concurrent programming. What is Concurrency Applications are expected to do more than one task at the same time in parallel. Applications which do more than one tasks at a time are called concurrent applications. An example of such concurrent software application is streaming audio application. It must read the digital audio from the network, decompress, manage playback and update the audio simultaneously. Process and Thread There are two basic units in the concurrent programming namely Process and Thread. 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What is Concurrency Applications are expected to do more than one task at the same time in parallel. Applications which do more than one tasks at a time are called concurrent…","_links":{"self":[{"href":"https:\/\/www.whizlabs.com\/blog\/wp-json\/wp\/v2\/posts\/8043","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.whizlabs.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.whizlabs.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.whizlabs.com\/blog\/wp-json\/wp\/v2\/users\/220"}],"replies":[{"embeddable":true,"href":"https:\/\/www.whizlabs.com\/blog\/wp-json\/wp\/v2\/comments?post=8043"}],"version-history":[{"count":1,"href":"https:\/\/www.whizlabs.com\/blog\/wp-json\/wp\/v2\/posts\/8043\/revisions"}],"predecessor-version":[{"id":76006,"href":"https:\/\/www.whizlabs.com\/blog\/wp-json\/wp\/v2\/posts\/8043\/revisions\/76006"}],"wp:attachment":[{"href":"https:\/\/www.whizlabs.com\/blog\/wp-json\/wp\/v2\/media?parent=8043"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.whizlabs.com\/blog\/wp-json\/wp\/v2\/categories?post=8043"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.whizlabs.com\/blog\/wp-json\/wp\/v2\/tags?post=8043"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\npublic class MyRunnable implements Runnable {
\npublic void run() {
\nSystem.out.println(\u201cMy first thread is running\u2026\u201d);
\n}
\npublic static void main(String\u2026 args) {
\nnew Thread(new MyRunnable()).start();
\n}
\n}
\n<\/code><\/p>\nWhy calling start()<\/i> method invokes run()<\/i> method<\/i><\/h5>\n
\n
By Extending Thread Class<\/h4>\n
\npublic class MyThread extends Thread {
\npublic void run() {
\nSystem.out.println(\u201cMy new thread from Thread class\u201d);
\n}
\npublic static void main(String\u2026 args) {
\nnew MyThread().start();
\n}
\n}
\n<\/code><\/p>\nImplementing Runnable vs. Extending Thread Class<\/h4>\n
\n