java methods tutorial

Bodhak java methods tutorial in this chapter we will discuss along with syntax’s and examples about Types of variables declared inside the class,  about instance variables,  about this keyword, Types of methods declared inside a class, about instance methods, Static methods/Class methods.

methods with parameters, Method with primitive type parameters, Method with reference type parameter, methods without parameters, method return Value Type, Method with primitive type return type, Method with reference type return type.


java methods tutorial

Java allows declaring two types of variables inside the class.

Nonstatic variables or Instance variables

Static variables or Class variables

Instance variables:

In object- oriented programming, an instance variable is a variable defined in a class, for which each object of the class has a separate copy or instance.

These are variables that are used to store the state of an object (for example, Name). They never have a static modifier attached to them. Every object created from a class definition would have its own copy of the variable. It is valid for and occupies storage for as long as the corresponding object is in memory.

About Instance variables:

When space is allocated for an object in the heap, a slot for each instance variable value is created.

Instance variables are created when an object is created with the use of the keyword ‘new’ and destroyed when the object is destroyed.

Instance variables hold values that must be referenced by more than one method, constructor or block, or essential parts of an object’s state that must be present throughout the class.

Instance variables can be declared in the class level before or after use.

Access modifiers can be given for instance variables (i.e. public, private, protected ).

The instance variables are visible for all methods, constructors, and block in the class. Normally, it is recommended to make these variables private (access level). However, visibility for subclasses can be given for these variables with the use of access modifiers.

Instance variables have default values. For numbers the default value is 0, for Booleans it is false and for object references it is null. Values can be assigned during the declaration or within the constructor.

Instance variables can be accessed directly by calling the variable name inside the class. However within static methods and different class ( when instance variables are given accessibility) should be called using the fully qualified name. ObjectReference.VariableName