Threads
Introduction
Classes and interfaces
Two ways to create a thread
- Inherit the Thread class.
- Implement the Runnable interface, then pass a reference to the Runnable object to the constructor of the Thread class. This is useful if the thread needs to inherit a class other than the Thread class.
Summary of classes and interfaces used for threading
| Class/Interface | Description | Thread | A class that defines a thread. This class inherits the Object class and implements the Runnable interface. | Runnable | An interface that must be implemented by any class whose objects are going to be executed by a thread. The only method in this interface is the run method. | Object | The Object class has several methods that are used for threading. |
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Key methods for threading
| Method | Class/Interface | Description | start | Thread | Registers this thread with the thread scheduler so it's available for execution. | run | Runnable, Thread | An abstract method that's declared by the Runnable interface and implemented by the Thread class. The thread scheduler calls this method to run the thread. | sleep | Thread | Causes the current thread to wait (sleep) for a specified period of time so the CPU can run other threads | wait | Object | Causes the current thread to wait until another thread calls the notify or notifyAll method for the current object. | notify | Object | Wakes up one arbitrary thread that's waiting on this object. | notifyAll | Object | Wakes up all the threads that are waiting on this object. |
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