.

In Java, access specifiers (also known as access modifiers) are keywords that determine the visibility and accessibility of classes, fields, methods, and constructors within a program. There are four main access specifiers in Java:

1. **Public (public):**

   - Members declared as public are accessible from any other class.

   - There is no restriction on their visibility.

2. **Private (private):**

   - Members declared as private are only accessible within the same class.

   - They are not visible to any other class, even subclasses.

3. **Protected (protected):**

   - Members declared as protected are accessible within the same class, the same package, and subclasses in other packages.

   - They are not accessible to non-subclasses in other packages.

4. **Default (no modifier):**

   - If no access specifier is used, the member is considered to have default visibility.

   - Members with default visibility are accessible only within the same package.

   - They are not accessible to classes outside the package, even if they are in subclasses.

Here's an example to illustrate these access specifiers:

```java

package com.example;  // This is a package declaration

public class MyClass {

    public int publicField;  // Accessible from anywhere

    private int privateField; // Accessible only within MyClass

    protected int protectedField; // Accessible within MyClass, same package, and subclasses

    int defaultField; // Accessible within MyClass and the same package

    public void publicMethod() {

        // Accessible from anywhere

    }

    private void privateMethod() {

        // Accessible only within MyClass

    }

    protected void protectedMethod() {

        // Accessible within MyClass, same package, and subclasses

    }

    void defaultMethod() {

        // Accessible within MyClass and the same package

    }

}

```

It's important to choose the appropriate access specifier based on the desired level of encapsulation and visibility for your classes and class members to maintain code integrity and security.