In This Article, You Will Learn to know about Java Access Specifier.
Java Access Specifier – Before moving ahead, let’s know a bit about Data Types in Java.
Table of Contents
Access Specifier
Access Specifier – It is a restriction line in Java that allows to access of class object, variable etc., but with some restriction.
E.g., A protected class instances can be accessed within same class but not from different package non-subclass.
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Types of Access Specifier
Public specifier
Public specifier allows to accessible of instances (method, object, variable) publically by all classes.
Private specifier
Private specifier allows to accessible of instances from only to its own class.
Protected specifier
Protected specifier allows to accessible of instances from the same package or by subclasses in different package.
Default specifier
Default specifier allows to accessible of instances from only to its own package.
Methods
Method
The method is collection of instructions or block of code that can do a specific task.
Method Signature
It is a part of the method declaration. It includes the method name and parameter list.
Method Body
It is a part of the method declaration which contains all the tasks to be performed. It is enclosed within the pair of curly braces.
Return Type
Every method returns some value which is known as Return type. It may return a primitive data type, object etc. If the method does not return anything, we use void keyword.
Naming a Method
The method name must start with a lowercase letter. In the multi-word method name, the first letter of each word must be in uppercase except the first word.
Example:
Single-word method name: sum(), add(), area() etc.
Multi-word method name: areaOfTriangle(), perimeterOfCircle, stringAdd() etc.
Types of Method
There are two types of methods in Java. Predefined Method and User-defined Method.
Pre-defined
Pre-defined is built-in/already defined method. Ex: equals(), length(), sqrt(), etc. Java doesn’t allow any modification in it.
E.g., Find the square-root of 25.
public class Main{
public static void main(String[] args){
System.out.println(Math.sqrt(25));
}
}
In this example, three built-in methods namely main(), print(), and sqrt() have been used. You can see these methods have been used directly without declaration because they are predefined. The sqrt() method is a method of the Math class which returns the square root of a number.
User-defined
User-defined is type of method that is written by user, it can be modified as per need. Ex: myName(), totalNum(), etc.
If you find anything incorrect in the above-discussed topic and have further questions, please comment below.
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