Java - (Field|Member Variable)

Java Conceptuel Diagram

About

A field is a variables in a class and they are used to contain state information. They are also known as member variable.

A member that is not declared as static is implicitly an instance member.

Field

Initialization

Fields are initialized when class is loaded into memory. They are initialized from top to bottom in the order they are declared in Java source file.

Declaration

Field declarations are composed of three components, in order:

  • 1. Zero or more modifiers, such as public or private.
  • 2. The field's type (datatype).
  • 3. The field's name.
public int cadence;

The public keyword identifies these fields as public members, accessible by any object that can access the class.

Modifiers

Java - Static Modifier

Access

The first (left-most) access modifier used lets you control what other classes have access to a member field. For the moment, consider only public and private.

  • public modifier—the field is accessible from all classes.
  • private modifier—the field is accessible only within its own class.

In the spirit of encapsulation, it is common to make fields private. This means that they can only be directly accessed from their owne class. We still need access to these values, however. This can be done indirectly by adding public methods that obtain the field values





Discover More
Code Refactoring
Code - Refactoring

The process of modifying the code structure, without modifying its current behavior, is called Refactoring. Refactoring is a method that search to improve the code quality of a program. code duplication...
Jpa Mapping Method
JPA - Entity Annotations

A key feature of EJB 3.0 and JPA is the ability to create entities that contain object-relational mappings by using (metadata) annotations rather than deployment descriptors (orm.xml) as in earlier versions....
Jdeveloper Create Managed Bean
JSF - (Managed Bean|Controller)

Managed Beans (also known as model objects and controllers) are lightweight container-managed objects (POJOs) with minimal requirements. They support a small set of basic services, such as: resource...
Java Conceptuel Diagram
Java - (Class|Object|Member) (Initialization|Instantiation)

Class (Initialization|Instantiation) in java. During an class initialization: Java's class loader loads the main method Java's byte code verifier verifies the class. The first initialization...
Classes Access
Java - Access Modifier (private, public, )

in Java. Access level modifiers determine whether other classes can use a particular field or invoke a particular method. There are two levels of access control: At the top level: public, or package-private...
Java Conceptuel Diagram
Java - Annotations

Since Java version 1.5. An annotation is an element of the java programming language (modifier or Metadata tag) that can be associated with: Java classes, interfaces, constructors, methods,...
Java Conceptuel Diagram
Java - Class Variable (Static Fields)

A class variable is any field declared with the modifier static. A field defining the number of gears for a particular kind of bicycle could be marked as static since conceptually the same number...
Java Conceptuel Diagram
Java - Constant

The names of constant fields are in upper-case letters. By convention, the names of constant values are spelled in uppercase letters. If the name is composed of more than one word, the words are separated...
Java Conceptuel Diagram
Java - Final Modifier

Final is modifier prohibiting value modification. Declaring an entire class final prevents the class from being subclassed. This is particularly useful, for example, when creating an immutable...
Java Conceptuel Diagram
Java - Member of a class

The members of a class are the inherited components of the class body including: fields, methods, nested classes, interfaces, and enumerated types. Since constructors are not inherited,...



Share this page:
Follow us:
Task Runner