Private Inwards Java: Why Should Y'all Ever Continue Fields In Addition To Methods Private?
Friday, December 21, 2018
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Making members private inwards Java is ane of best coding practice. Private members (both fields as well as methods) are only accessible within the class they are declared or within inner classes. private keyword is ane of 4 access modifier provided past times Java as well as its a most restrictive with all 4 e.g. public, default(package), protected as well as private. Though in that place is no access modifier called package, rather its a default access aeroplane provided past times Java. In this Java tutorial nosotros volition come across why should nosotros e'er brand members of aeroplane past times default every bit private as well as answer to one of popular Java interview question can override private methods inwards Java.
This article is inwards continuation of my before post on Java e.g. 10 Object Oriented Design principles Java programmer should know as well as 10 best exercise to follow patch writing comments. If y'all haven’t read them already y'all may uncovering them interesting as well as worth reading.
Why should y'all brand your members private past times default:
concept of Encapsulation inwards Java. Here are about benefits of making variables or methods private in Java: 1) private methods are good encapsulated inwards aeroplane as well as developer knows that they are non used anywhere else inwards code which gives them confident to change, modify or heighten private method without whatever side-effect.
2) By looking to the private method y'all know past times certain that no ane is using it which is bully assistance during debugging coffee program.
3) IDE similar Netbeans as well as Eclipse occupation this information as well as automatically cheque whether private methods are used within Class or non as well as tin laissez passer on notice display relevant warning to improve code quality or delete unused statements, variables or methods.
4) private methods occupation static binding inwards Java as well as they are bonded during compile fourth dimension which is fast compared to dynamic binding which occurs during runtime as well as too gives run a endangerment to JVM to either inline the method or optimize it.
5) Making variables person inwards coffee as well as providing getter as well as setter for them makes your aeroplane compatible Java edible bean naming convention as well as other reflection based frameworks similar displaytag .
Can nosotros override Private method inwards Java
No y'all cannot override private methods inwards Java, private methods are non virtual as well as accessed differently than non-private methods. Since method overriding can exclusively locomote done on Sub Class as well as since private method is non accessible inwards sub aeroplane or derived class, You but tin laissez passer on notice non override them. Another possibility of overriding private methods inwards inner aeroplane by extending outer class, since private methods are accessible within inner class. This volition too non piece of work because private methods are bonded during compile fourth dimension as well as exclusively Type (or Class) which is used to locate a private method. For event inwards below code where it looks similar Inner SubClass is overriding private method , if y'all telephone telephone privateMethod() with a type of Super Class but object of Sub Class, it volition exclusively execute privateMethod() declared inwards super Class.
Should I e'er brand private method every bit concluding inwards Java
Using concluding as well as private inwards Java with method is a expert pick but I don't think it offering whatever do goodness inwards damage of performace or not. Rather this determination should locomote taken on the footing of design, functionality as well as ensuring readability of code. Since making a method concluding but bound in that place might to locomote overridden, it doesn't brand much feel to score a private method every bit concluding inwards java, because private method tin laissez passer on notice non overridden inwards Java past times whatever means.
Important Points nearly private keyword inwards Java
Few important points to recall nearly private keyword inwards coffee before seeing event of private keyword as well as overriding person methods inwards Java which is non possible.
1.private keyword tin laissez passer on notice locomote applied to fields, methods as well as inner aeroplane inwards Java.
3.Though private methods or variables are non accessible exterior of Class, they tin laissez passer on notice locomote accessed via reflection past times using setAccessible(true) as well as changing in that place private visibility.
4.Private method tin laissez passer on notice non locomote overridden inwards Java, non fifty-fifty within inner classes.
5.private members allows Compiler as well as JVM to optimize it for amend performance.
Example of person champaign as well as method inwards Java
Here is a code event or private keyword inwards Java. This examples shows that private methods uses static binding at compile fourth dimension as well as tin laissez passer on notice non locomote overridden. Don’t confuse with the output though regarding private variable because its accessible within Inner classes. It volition locomote compiler mistake if private variables used exterior the class.
public class PrivateMemberExample {
private String i_m_private = "I am person member, non accessible exterior this Class";
private void privateMethod() {
System.out.println("Private method of Outer Class");
}
public static void main(String args[]) {
PrivateMemberExample outerClass = new PrivateMemberExample();
NestedClass nc = outerClass.new NestedClass();
nc.showPrivate(); //shows that person method are accessible inwards inner class.
outerClass = nc;
nc.privateMethod(); //does non telephone telephone person method from inner aeroplane because
// y'all tin laissez passer on notice non override person method within inner class.
}
class NestedClass extends PrivateMemberExample {
public void showPrivate() {
System.out.println("Accessing Private members of Outer class: " + i_m_private);
privateMethod();
}
private void privateMethod() {
System.out.println("Private method of Nested Class");
}
}
}
Output:
Accessing Private members of Outer class: I am private member, non accessible exterior this Class
Private method of Outer Class
Private method of Outer Class
private String i_m_private = "I am person member, non accessible exterior this Class";
private void privateMethod() {
System.out.println("Private method of Outer Class");
}
public static void main(String args[]) {
PrivateMemberExample outerClass = new PrivateMemberExample();
NestedClass nc = outerClass.new NestedClass();
nc.showPrivate(); //shows that person method are accessible inwards inner class.
outerClass = nc;
nc.privateMethod(); //does non telephone telephone person method from inner aeroplane because
// y'all tin laissez passer on notice non override person method within inner class.
}
class NestedClass extends PrivateMemberExample {
public void showPrivate() {
System.out.println("Accessing Private members of Outer class: " + i_m_private);
privateMethod();
}
private void privateMethod() {
System.out.println("Private method of Nested Class");
}
}
}
Output:
Accessing Private members of Outer class: I am private member, non accessible exterior this Class
Private method of Outer Class
Private method of Outer Class
In Summary private keyword inwards java allows most restrictive access to variables as well as methods as well as offering strongest shape of Encapsulation. private members are non accessible exterior the aeroplane as well as private method tin laissez passer on notice non locomote overridden.
Further Learning
Complete Java Masterclass
10 JVM options Java programmer should know
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