Technology for All
NumberFormatException occurs in Java when we are trying to convert string into some numeric type but string is not in the correct format. It usually occurs when we parse string to integer, double, long etc datatypes but string is not present in correct format. Let us see an example code : Output Since ‘123a’ cannot … Read more
In Java we have 4 type of variables :- Local Variable Instance Variable Class variable Reference variable Java developers often get confused while using these terms, let us understand the difference between them in detail : Local Variable Local variables are those which are defined inside a block, method or constructor. These variables get destroyed … Read more
PI value in mathematics is a very important value used in number of formulas. In java value of PI can be obtained through Math class of java.lang package. Math.PI is a double constant whose value = 3.141592653589793 Let us look at a program to calculate area of circle using Math.PI Output
Declaration, Instantiation and Initialization are very confusing terms in Java. Let us clear their meanings with example : Declaration A variable is said to be declared when we give name to variable and associate it with a class. Example :- Student stu; (here Student is a class) Instantiation Instantiation means we are creating an object … Read more
The class whose only one object can be created is called Singleton class. Now a days questions on Singleton class have become very common in interviews and other exams. So it is very important for every developer to have knowledge of Singleton class. Features of Singleton class : Only one object can be created of … Read more
Quicksort is an optimized sorting algorithm. It makes use of divide and conquer logic to sort the series. Let us understand: How Quicksort works (Easy Explanation) : The array obtained at the end will be sorted. Take a look at below image to get more clarity on steps:- Let us take take a look at … Read more
In selection sorting each element is compared with all the following elements of the array. If the element is greater than any following element then swapping is done. After the first cycle we obtain the smallest element at the starting. Now in the second cycle, second element is compared with all following elements to obtain … Read more
Bubble sorting and Linear sorting are the easiest methods of sorting. Also they are the least optimized sorting algorithms. First we are going to look at bubble sorting in java. In Bubble sort each element is compared with its next element, if the element is greater than the next element then they are swapped. This … Read more
Sorting is the process through which elements can be arranged in ascending or descending order. Sorting can be done on numbers, strings etc. In Java inbuilt functions are also available to directly sort the series. These inbuilt functions are provided by Collections framework in Java. Example :- Unsorted series = 24, 20, 100, 203, 1, … Read more
In previous post we saw how to download eclipse and create a new workspace. Now let us see how to create a new Java project, program and run the program in Eclipse. Steps to create and run Java program : Step 1 : After eclipse has opened, a welcome screen will appear. You can explore … Read more