What are the levels of access to class members in Java?

In Java, there are four main access levels for class members (fields and methods):

1. public — accessible from anywhere, any class.
2. protected — accessible within the same package and in subclasses (even if in different packages).
3. default (package-private) — if no access modifier is specified, accessible only within the same package.
4. private — accessible only within the class itself, not outside.

Example:

public class Example {
    public int publicField;
    protected int protectedField;
    int defaultField; // package-private
    private int privateField;
}

Choosing the access level helps encapsulate data and control the visibility of class members.