Core java

In this article, we are going to find first and last digit of a number. To find first and last digit of any number, we can have several ways like using modulo operator or pow() and log() methods of Math class etc. Let’s see some examples. Before moving to example, let’s first create an algorithm […]

In this article, we will learn to initialize 2D array in Java. The array is a data structure that is used to collect a similar type of data into contiguous memory space. An array can be a single-dimensional or multidimensional. An array that has 2 dimensions is called 2D or two-dimensional array. There are several […]

In this article, we are going to learn to find Happy Number using Java. Let’s first understand, what is Happy Number? What is a Happy Number? A number which leaves 1 as a result after a sequence of steps and in each step number is replaced by the sum of squares of its digit. For […]

In this article, we will learn to initialize ArrayList with values in Java. ArrayList is an implementation class of List interface in Java. It is used to store elements. It is based on a dynamic array concept that grows accordingly. We can Initialize ArrayList with values in several ways. Let’s see some of them with […]

In this article, we will learn to get thread id of a running thread in Java. An Id is a unique positive number generated at the time of thread creation. This id remains unchanged during the lifetime of the thread. When a thread gets terminated its id can be used to refer another thread, but […]

Learn about how to compare characters in java using different methods.

In this article, we are going to find whether a number is perfect or not using Java. A number is called a perfect number if the sum of its divisors is equal to the number. The sum of divisors excludes the number. There may be several approaches to find the perfect number. For example: 28 […]

In this post, we will see how to do input validation in java using Scanner class. The Java Scanner class is used to get input from user. It provides several methods to get input of different types and to validate the input as well. Here we will see some of these methods that can be […]

In this article, we are going to learn to find Magic Number using Java. Let’s first understand, what is Magic Number? What is a Magic Number? A number which leaves 1 as a result after a sequence of steps and in each step number is replaced by the sum of its digits. For example, if […]