Interview Questions, Answers and Tutorials

Month: July 2018

09.2 Control Flow

9.2 | Looping Statements Java supports four looping statements. for…statement for each…statement while…statement do-while…statement   for …statement   It executes a block of code a specified number of times.      For example – the code below prints numbers from 1 to 9.   for…each statement   It executes a block of code for each item in a collection or each element in an array.   For example – the code below prints all numbers in an array.     while…statement   It executes a block of code while or until the condition is true.   For example – The…

09.1 Control Flow

Java, like any other programming language, supports both conditional and loop statements to control code flow.   9.1 | Conditional Statements   In Java, we have four conditional statements: 1. if(condition=true){}: Execute a set of code when the specified condition is true.  2. if(condition=true){}else{}: Execute first block of code when the specified condition is true else executes the second block of code.  3. if(condition1=true){}elseif{condition2=true}{}else{}: Execute the first block of code for which the condition is true. If no condition is found true and else block exists, then this block of code is executed. If no condition is found true and…

08 Arrays

8.1 | Arrays An array is a data structure that stores a collection of values of the same data type. Values stored in the array are accessible through the array index //Declaring an array of integers int arr1[];   //Creating an integer array with values int[] arr0 = {2,3,4,5,6,7};   //Creating an integer array which can hold 100 integers int arr2[] = new int[100]; //Or, int arraySize = 100; int arr3[] = new int[arraySize]; //Assigning values to the array arr3[0] = 1; arr3[1] = 2; //Creating a string array which can hold 100 values String arr4[] = new String[100];  …

07 Data Types, Literals, Variables, Expressions, and Operators

7.1 | Data Types   Each variable declaration in Java must define the data type of the variable. The data type defines what values a variable can store. The variable type can be as follows: One of the eight basic primitive data types An Array The name of a class The eight primitive data types hold values for integers, floating-point numbers, characters, and boolean values. They are called primitive because they are built into the system and are not actual objects. This makes them more efficient to use.   Data Type Width (bits) Minimum value/ Maximum value boolean NA True, false…

06 Introduction to Java

Java is an object-oriented programming language (OOP) developed by Sun Microsystems, which enables programmers to create flexible, modular, and reusable codes. The important feature of OOP language which help programmers achieve this are encapsulation, polymorphism, and inheritance.  Encapsulation: It is a mechanism that binds together codes and data and manipulates to keep the code safe from outside interference and misuse. Java implements encapsulation by defining the accessibility condition of variables, methods, and classes (private, protected, and public). Java’s basic unit of encapsulation is class. A class specifies the data and the code that will operate on the data. A class…