Java - Data Types

Java Data Types

Java is statically typed and also a strongly typed language because, in Java, each type of data (such as integer, character, hexadecimal, packed decimal, and so forth) is predefined as part of the programming language and all constants or variables defined for a given program must be described with one of the Java data types.

Java has two data types,

    1)  Primitive data types.

    2)  Non-Primitive data types.

Primitive data types.

Primitive data are only single values and have no special capabilities. There are 8 primitive data types.

    1. boolean

  • The boolean data type represents a logical value that can be either true or false.

    2. byte

  • The byte data type is an 8-bit signed two’s complement integer. The byte data type is useful for saving memory in large arrays.

    3. short

  • The short data type is a 16-bit signed two’s complement integer. Similar to byte, use a short to save memory in large arrays, in situations where the memory savings actually matters.

    4. int

  • It is a 32-bit signed two’s complement integer.

    5. long

  • The range of a long is quite large. The long data type is a 64-bit two’s complement integer and is useful for those occasions where an int type is not large enough to hold the desired value.

    6. float

  • The byte data type is an 8-bit signed two’s complement integer. The byte data type is useful for saving memory in large arrays.

    7. double

  • The byte data type is an 8-bit signed two’s complement integer. The byte data type is useful for saving memory in large arrays. (ex: 5.5)

    8. char

  • The byte data type is an 8-bit signed two’s complement integer. The byte data type is useful for saving memory in large arrays.


Non-primitive data types.

    1. String

  • Strings are defined as an array of characters. The difference between a character array and a string in Java is, that the string is designed to hold a sequence of characters in a single variable whereas, a character array is a collection of separate char-type entities.

    2. Class

  • A class is a user-defined blueprint or prototype from which objects are created. It represents the set of properties or methods that are common to all objects of one type.

    Ex: Modifires, Class name, Superclass, Interfaces, Body{}

    3. Object

  • An Object is a basic unit of Object-Oriented Programming and represents real-life entities.

    Ex: State, Behavior, Identity

    4. Interface

  • Like a class, an interface can have methods and variables, but the methods declared in an interface are by default abstract (only method signature, no body).

    5. Array

  • An Array is a group of like-typed variables that are referred to by a common name.


Summary 

Understanding Java’s data types is fundamental to efficient programming. Each data type has specific use cases and constraints, making it essential to choose the right type for the task at hand. This ensures optimal memory usage and program performance while leveraging Java’s strong typing system to catch errors early in the development process.




Comments

Post a Comment

Popular posts from this blog

Java Language - Object Generating & Objects / Java classes

Image
Java Object  Generating & Objects An object is an instance of a class.  A class is a template or blueprint from which objects are created. So, an object is the instance(result) of a class. Object is a super class. Object Definitions: An object is  a real-world entity . An object is  a runtime entity . The object is  an entity which has state and behavior . The object is  an instance of a class.
Read more

Introduction of Java Programming Language

Image
Java Programming Language  Java is a high-level, class-based, object-oriented programming language that is designed to have as few implementation dependencies as possible. This well-known programming language was developed in 1995. Oracle owns it, and Java is used on over 3 billion devices. James Gosling (farther of java) Java was originally developed by James Gosling at Sun Microsystems. It was released in May 1995 as a core component of Sun's Java platform. The original and reference implementation Java compilers, virtual machines, and class libraries were originally released by Sun under proprietary licenses. The language was initially called Oak after an oak tree that stood outside Gosling's office. Later the project went by the name Green and was finally renamed Java, from Java coffee, a type of coffee from Indonesia.[23] Gosling designed Java with a C/C++-style syntax that system and application programmers would find familiar. JVM (Java Virtual Machine) A Java Virtual M...
Read more

Java Standards

Image
Java Standards In Java, the coding guidelines are the set of rules that are followed by the developer during application development. These guidelines provide readability to other developer and user who are dealing with the project. The guidelines must be followed because an application is not developed by a single programmer. Some major coding guidelines includes the following: Naming conventions Curley Braces Indentation White spaces Comments Naming conventions These are the rules for naming variables, methods, constants, classes, interfaces, etc. Generally, Java follows the camel case convention. It describes the following: The class and interface name must be noun, and the first letter of each internal word should be capitalized. Ex: Gun , Man The method name must be verb in mixed case, each first letter should be in lower case with the first letter of each internal word should be capitalized. Ex:   main() ,  methodA() All the constants should be in capital letters. ...
Read more