What is the default access modifier in Java?

Class and members: tweak it, don't leak it

When a class doesn’t shout out an access modifier, it opts for a silent vow and becomes package-private by default. This means it can't sneak its way out of its own package.

Members of the class (fields, methods, constructors) follow the same etiquette:

package mypackage;

class MyPackageClass { // Only cool for mypackage crowd
    void printSecret() {  // Our secret's safe in mypackage
        System.out.println("It's a secret to everyone… but us!");
    }
}

public class MyPublicClass {
    MyPackageClass myObj = new MyPackageClass(); // "Yep, I know secrets!"
    // Can call myObj.printSecret() here inside my-package, it's our juicy gossip!
}


In this snippet, MyPackageClass and its method printSecret() can no longer hold their tongue outside the confines of mypackage. So, beware, subclasses from other packages cannot access package-private superclass members.

As they say, "protected is the new black" for those subclasses.

package anotherpackage;

import mypackage.*;

public class IntrusiveClass extends MyPackageClass {
    // printSecret(): "It's a secret and we're not telling!"
}


Interface: the public meeting

In the world of interfaces, rules are different: methods and variables are public and static. No need to wave the public sign, they jump right into the public domain by default.

interface Party {
    int MAX_GUESTS = 200;  // Public notice: "Party capacity!"
    void invitation(); // Public call: "Everyone's invited!"
}


Shy about declaring your intentions? Hold up, the Java police will mark those as public anyway!

Moonwalk around access levels

Understanding the default access modifier is like the dance move – essential for juggling code visibility and the hoop of encapsulation. Dancing to the beats of default access, developers can achieve finer control while mixing and matching code components.

Default: Unveiling the common misconceptions

Cross-package access misunderstanding

Some devs might treat package-private members as social butterflies, expecting them to be sociable within subclasses residing in different packages. But reality check, unlike a 'protected' access, default access levels stand with a "No Entry without invitation" board for suchcross-package accessibility.

Interface member mix-up

A common stumble is to think that members of an interface stress out and take package-private as their default state, just as their class member counterparts. Newsflash: They are public and static by default.

Implicit = Explicit?

Devs may drip into the default access modifier, not by artful design, but by oversight. Raise the access level if your design code of conduct demands it.

The loophole and the trapdoor

Fashioning of class structures necessitates caution. Package-private access can be your secret weapon, but lax handling can stroke it into a loose cannon, leading to tight coupling of components and hazy interfaces.