The formula for calculating area of a circle is, Area = PI * r * r, where PI is a constant and r is the radius of the circle. The following sample Java program calculates area of a circle. The radius of the circle is taken as user input from command line. The default Java […]

Java has plenty of classes for file manipulation. For simple text files which contains lines of text, the best classes to use are FileWriter and PrintWriter in java.io package. PrintWriter has the method println() which writes a string into the file followed by a new line. Also note that PrintWriter and FileWriter must be closed […]

One of the common string processing requirements in computer programs is to split a string into sub strings based on a delimiter. This can be easily achieved in Java using its rich String API. The split function in String class takes the delimiter as a parameter expressed in regular expression form. The following Java program […]

Printing asterisk triangle is common programming problem given to beginners learning Java language. This will help students to grasp the power of loop programming construct. There are a number of variants of this problem. The following example shows how a triangle pyramid can be printed using Java. * *** ***** ******* ********* *********** ************* *************** […]

Simple programming problems such as multiplication of numbers is a good way to teach programming syntax without students getting overwhelmed by the programming solution. The following Java program demonstrates multiplication of two numbers. This is a trivial example program, however it shows how to handle input and output, performing calculations and the use of library […]