Java Core Classes and Threads

The countTokens() method is used to calculate the number of times the tokenizer's nextToken method can be called before it generates an exception

We can create a new thread using two ways:

1. Declare a class to be a subclass of Thread class.
2. Declare a class that implements the Runnable interface.

The code we want to execute has to be place in a method run() of the class which extends class Thread. This function will automatically call by using start().

The correct structure is: class MyClass extends Thread {       public void run()       {       } }

The join() method of thread class makes the current thread to wait until other specified thread terminates.

All these methods must be called only when they own the monitor of that object, otherwise they throw IllegalMonitorStateException exception. These methods are used for proper coordination among the threads.

The package java.util gives two very useful classes, i.e. Timer and TimerTask. These classes are used for conjunction.

There are four constructors for a Timer class:

1. Timer()
2. Timer(Boolean isDaemon)
3. Timer(String name)
4. Timer(String name,Boolean isDaemon)

A. The sleep() method is used to temporarily stop the execution of the thread. B. The join() method is used to wait for this thread to die.

The destroy() method of thread class destroys this thread, without any clean-up.

The package java.lang defines a class Throwable.

The ArrayIndexOutOfBoundsException occurs if one is trying to access an element of array with an index that is larger than the range. For example: int Num[]={0,2,3}; Num[5]=0; /This statement throws the exception/

The exception ClassCastException is not a sub-class of RuntimeException.

An instance of ThreadDeath is thrown in the victim thread when the stop method is called with zero arguments in class Thread.

The return type of start() method is void, i.e. void start().