Java provides various datatypes to store various data values. It provides 7 primitive datatypes (stores single values) namely, boolean, byte, char, short, int, long, float, double and, reference datatypes (arrays and objects).Casting in JavaConverting one primitive data type into another is known as type casting. There are two types of casting −Widening− Converting a lower datatype to a higher datatype is known as widening. It is done implicitly.Narrowing− Converting a higher datatype to a lower datatype is known as narrowing. You need to do it explicitly using the cast operator (“( )”).For every primitive variable a wrapper class is available, ... Read More

While reading the contents of a file in certain scenarios the end of the file will be reached in such scenarios a EOFException is thrown.Especially, this exception is thrown while reading data using the Input stream objects. In other scenarios a specific value will be thrown when the end of file reached.Let us consider the DataInputStream class, it provides various methods such as readboolean(), readByte(), readChar() etc.. to read primitive values. While reading data from a file using these methods when the end of file is reached an EOFException is thrown.ExampleFollowing program demonstrates how to handle the EOFException in Java. Live ... Read More

The read() method of the input stream classes reads the contents of the given file byte by byte and returns the ASCII value of the read byte in integer form. While reading the file if it reaches the end of the file this method returns -1.ExampleAssume we have a text file (sample.txt) in the current directory with a simple text saying “Hello welcome”. Following Java program reads the contents of the file byte by byte using the read() method and prints the integer value returned for each byte.Since we are not checking for end of the file, the read() method ... Read More

When a class has two or more methods by the same name but different parameters, at the time of calling based on the parameters passed respective method is called (or respective method body will be bonded with the calling line dynamically). This mechanism is known as method overloading.Exampleclass Test{ public int division(int a, int b){ int result = a/b; return result; } public double division (float a, float b){ double result = a/b; ... Read More

When a class has two or more methods by the same name but different parameters, at the time of calling based on the parameters passed respective method is called (or respective method body will be bonded with the calling line dynamically). This mechanism is known as method overloading.Example Live Democlass Test{ public int division(int a, int b){ int result = a/b; return result; } public double division (float a, float b){ double result = ... Read More

When a class has two or more methods by the same name but different parameters, at the time of calling based on the parameters passed respective method is called (or respective method body will be bonded with the calling line dynamically). This mechanism is known as method overloading.Operator overloadingOperator overloading is the ability to redefine the functionality of the operators. Programming languages like c++ supports operator overloading.you can redefine or overload most of the built-in operators available in C++. Thus, a programmer can use operators with user-defined types as well.Overloaded operators are functions with special names: the keyword "operator" followed ... Read More

In Java you can copy an object in several ways, among them, copy constructor and the clone method are the mostly used.Using copy constructorGenerally, the copy constructor is a constructor which creates an object by initializing it with an object of the same class, which has been created previously. Java does support for copy constructors but you need to define them yourself.ExampleIn the following Java example, we a have a class with two instance variables name and age and a parameterized constructor initializing these variables.Then, we have another constructor which accepts an object of the current class and initializes the ... Read More

In Java, a JComboBox is a component that displays a drop-down list and gives users options that we can select one and only one item at a time whereas a JList shows multiple items (rows) to the user and also gives an option to let the user select multiple items. JComboBox A JComboBox can be editable or read-only. An ActionListener, ChangeListener, or ItemListener interface can be used to handle the user actions on a JComboBox. Syntax The following is the syntax for JComboBox initialization: String[] fruits = {"Apple", "Banana", "Orange", "Mango"}; JComboBox comboBox = new JComboBox(fruits); We can create a ... Read More

A SwingWorker class enables us to perform an asynchronous task in a worker thread (such as a long-running task) then update Swing components from the Event Dispatch Thread (EDT) based on the task results. It was introduced in Java 1.6 Version.SwingWorker classThe java.swing.SwingWorker class is a task worker, which performs time-consuming tasks in the background.A SwingWorker instance interacts with 3 threads, Current thread, the Worker thread, and the Event Dispatch thread(EDT).The Current thread calls the execute() method to kick off the task to the background and returns immediately.The Worker thread executes our own version of the doInBackground() method continuously in the background.The Event Dispatch Thread (EDT) wakes up from time to ... Read More

In this article, we will learn about the differences between a MouseListener and a MouseMotionListener in Java. We can implement a MouseListener interface when the mouse is stable while handling the mouse event, whereas we can implement a MouseMotionListener interface when the mouse is in motion while handling the mouse event. Mouse Listener A MouseListener is fired when we press, release or click (press followed by release) a mouse button (left or right button) at the source object or position the mouse pointer at (enter) and away (exit) from the source object. Abstract Methods A MouseListener interface declares the following five ... Read More