Java Tutorial

by Dinesh Thakur Category: Swing
 
by Dinesh Thakur Category: Swing
 
by Dinesh Thakur Category: Swing

The flow layout manager is the simplest of all the layout managers. It positions the components in the order they are added to the container. It places the components from left to right, that is, horizontally. Once a row gets completely filled with components then the remaining components are placed in the next row. It is the default layout manager for Applet and Panel. Each component is evenly separated from its neighboring components by leaving a small space not only from above and below it, but also from left and right.

 
by Dinesh Thakur Category: Swing
 
by Dinesh Thakur Category: Swing

The most common use of inner classes is with event handling. An inner class can be used to implement a particular listener interface or to subclass a particular adapter. This has the benefit of separating out the control aspect of the interface from the display elements. It also means that the event handler inner class can inherit from a different class to the encompassing class.

 
by Dinesh Thakur Category: Swing
 
by Dinesh Thakur Category: Java Methods

In this program, user is asked a number to enter which is stored in integer form in variable n. The value entered is say 1023.Now, this value of variable n is passed to parameter x by invoking revers() method. In revers() method, x is divided by 10 and the remainder is displayed (% returns remainder). When 1023 is divided by 10, the remainder will be 3 which is displayed on the screen. Then, again revers() is invoked with value 102/10 i.e. with 102 (because the output of dividing two integers is also an integer). 102 is assigned to variable x. Again, 102 is divided by 10 and the remainder is displayed. The remainder this time will be 2 which is displayed. Again revers() method is invoked with 10/10 i.e. which 1. And the process continues until value of x becomes 0.

 
by Dinesh Thakur Category: Java Methods

There are two ways of passing arguments to a method (function/subroutine):

1. Call by Value

This method copies the value of an argument into the formal parameter of the method. Therefore, changes made to the parameter of the method are limited to that method only and there is no impact of changes on the argument. That is, when control returns back to the caller method, earlier values of the arguments will be seen.

 
by Dinesh Thakur Category: Java Methods

Recursion occurs when a function calls itself in its own body. That is, in the body of the function definition there is a call to itself. When the function calls itself in its body, it results in an infinite loop. So, there has to be an exit condition in every recursive program.

 
by Dinesh Thakur Category: Java Methods

Accessor methods are used for initializing and accessing the value of instance variables. The value of these instance variables can be used further in the program. For creating accessor methods, it is required to create two methods among which one method is used to initialize the value and other is used to retrieve the value. An accessor method makes the program more readable and understandable. Moreover, accessor methods are similar to any other method, as can be seen from Program.

 
by Dinesh Thakur Category: Java Methods

To create a class variable or method, include the word static in front of the method's name. The modifier static typically comes after any protection modifiers. Given below is an example that illustrates how a class variable may be created in a program.

 
by Dinesh Thakur Category: Java Methods

Since the string variable str is static, it is initialized to "This is second line displayed" (static variables are initialized before an object is initiated). Then, the static block is executed which will invoke the disp() method displaying the message: "This is first line displayed". Static() method can be invoked without the need of any object. In main(), again disp() method is called with the string str (This is second line displayed). After that an object SMV is made, and it will get a member str2 initialized to "This is last line displayed". Then disp() is called with SMV.str2 which displays: This is last line displayed on the screen

 
 
by Dinesh Thakur Category: Java Methods

A Java method is a collection of statements, all performing a particular operation.  Let’s say that you were calling the method called System.out.println(); Java executes some different statements that print a message to your console.  We’re going to look at the creation of methods or, as they often called, functions.

 
by Dinesh Thakur Category: Java Methods

Tail recursion occurring when the recursive call is at the end of the recursive instruction. This eliminates the potential problem of stack overflow. A call is tail recursive if nothing has to be done after the call returns. i.e. when the call returns, the returned value is immediately returned from the calling method.

 
by Dinesh Thakur Category: Java 2D Example

Point2D class does not draw anything; it is the representation of points Java2D. But yes you can draw shapes from points. Following is at able that lists some of the Constructors and methods of Point2D class:

 
by Dinesh Thakur Category: Java 2D Example

Another way is to build figures using GeneralPath class, which but also inherits from Shapeisan interface, but a class. This class allows  define a shape by a sequence oflines that can be established through  functions in the following table:

 
by Dinesh Thakur Category: Java 2D Example

The class that is used to draw rectangles and squares is the Rectangle2D. The constructor specifies the first two parameters of the corner position upper left relative to the coordinate system of the window.

 
by Dinesh Thakur Category: Java 2D Example

Draw a straight line is one of the easiest things to do with Java2D. This is achieved through the Line2D class, whose constructor accepts four parameters, namely the coordinates of the start and end respectively.

 


About Dinesh Thakur

Dinesh ThakurDinesh Thakur holds an B.SC (Computer Science), MCSE, MCDBA, CCNA, CCNP, A+, SCJP certifications. Dinesh authors the hugely popular blog. Where he writes how-to guides around Computer fundamental , computer software, Computer programming, and web apps. For any type of query or something that you think is missing, please feel free to Contact us.