Public access modifier in Java - Step-by-Step Execution

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Concept Flow - Public access modifier

Declare public class or member

↓

Accessible from anywhere

↓

Use in same class, package, or other packages

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No access restrictions

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Program runs

The public access modifier allows classes, methods, or variables to be accessed from any other class or package without restriction.

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Execution Sample

Java

public class Car {
    public String model = "Tesla";
    public void display() {
        System.out.println(model);
    }

    public static void main(String[] args) {
        Car c = new Car();
        c.display();
    }
}

This code defines a public class with a public variable and method, then creates an object and calls the method to print the model.

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Execution Table

Step	Action	Evaluation	Result
1	Create object c of class Car	new Car()	Object c created with model = "Tesla"
2	Call c.display()	c.display()	Prints: Tesla
3	Access c.model directly	c.model	Returns "Tesla"
4	Try access from another class/package	Access public member	Allowed, no error
5	End of execution	-	-

💡 Program ends after printing the model and demonstrating public access

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Variable Tracker

Variable	Start	After Step 1	After Step 2	Final
c	null	Car object with model="Tesla"	Car object with model="Tesla"	Car object with model="Tesla"
model	null	"Tesla"	"Tesla"	"Tesla"

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Key Moments - 2 Insights

▶Why can we access the variable 'model' directly from object 'c'?

▶What happens if we try to access a non-public member from another package?

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Visual Quiz - 3 Questions

Look at the execution table, what is printed when c.display() is called at step 2?

A Error

B null

C Tesla

D Nothing

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Concept Snapshot

public modifier allows access from anywhere
Used on classes, methods, variables
No restrictions on visibility
Syntax: public type name
Example: public int count;

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Full Transcript

The public access modifier in Java means that the class, method, or variable can be accessed from any other class or package without restriction. In the example, a public class Car has a public variable model and a public method display. When we create an object c of Car and call c.display(), it prints the model name 'Tesla'. Because model is public, we can also access c.model directly from anywhere. If a member is not public, accessing it from another package would cause a compile error. Public is the most open access level in Java.