What is the purpose and limitations of the internal scope in programming languages?

The internal visibility modifier in Kotlin (often used for Android development) means that the element (class, function, property) is visible only within a single module.

A module is a set of Kotlin files that are compiled together, for example, a single Gradle module.

Purpose:

• To restrict access to code so that it is only available within the module, not outside.
• It allows organizing encapsulation at the module level, which is more convenient than public (available everywhere) or private/protected (restricted to class or package).

Restrictions:

• internal does not allow using the element from another module, even if it is in the same project.
• When building into a single JAR or AAR, the module is usually the entire package, but when divided into multiple modules, access is restricted.

Example:

internal class InternalHelper {
    fun doSomething() {}
}

// The InternalHelper class will only be accessible within the current module.