# Author: Irfan Khan

- 09 October
### Initialize 2D array in Java

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 […]

- 09 October
### Java program to find first and last digit of a number

In this article, we are going to find first and last digit of a number in Java. 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 […]

- 02 October
### Initialize ArrayList with values in Java

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 […]

- 30 September
### Get Thread Id in Java

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 […]

- 30 September
### Find Perfect Number in Java

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 […]

- 29 September
### Input validation in java using Scanner

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 […]

- 15 April
### How to Deep Copy Arraylist in Java

Learn about how to create deep copy of ArrayList in different ways.

- 28 September
### PI in Java

The Pi is a constant value in Mathematics that represents a floating-point value 3.1415. It is mostly used in geometry to calculate area, circumference, volume, etc. If you have studied geometry in your academic, then you may be aware of use of Pi such as calculating area require this constant value. In Java, when we […]

- 28 September
### Number guessing game in java

In this article, we will implement Number guessing game in java. The number guessing game is based on a concept where player guesses a number between a range. If player guesses the exact number then player wins else player looses the game. Since this game provides limited attempts, so, player must guess the number with […]