Thread Creation

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What Does Thread Creation Mean?

Thread creation, in the context of Java, occurs either by extending the thread class or implementing the runnable interface.


In Java, an object of the thread class represents a thread. When a thread is first created, it must be permenantly bound to an object with a run() method; when invoked, it should invoke the object’s run() method.

Techopedia Explains Thread Creation

Implementing the runnable interface involves the following steps:

  1. A class implements the runnable interface and provides the run() method executed by the thread. An object that belongs to this class is a runnable object.
  2. The thread class object is created by passing the runnable object to the thread constructor.
  3. The start() method is invoked on the thread object created in the previous step.
  4. When the run() method ends, the thread also ends.

Extending the thread class involves the following steps:

  1. The java.lang.Thread class is extended by using extend.
  2. By overriding the run() method of the subclass extended from the thread class, the thread’s executed code is defined.
  3. An instance of this subclass is created.
  4. By invoking the start() method on this instance of the class, the thread runs.

The runnable interface is generally preferred over extending the thread class for two reasons:

  • A subclass cannot extend another class when extending the thread class. However, when using the runnable interface, the subclass can extend another class.
  • In some cases, the runnable interface is sufficient, as inheriting the whole class may lead to excessive overhead.

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Margaret Rouse
Technology Expert
Margaret Rouse
Technology Expert

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.