What are the ways to connect and use extensions in Java applications?

In Java applications, including Android, extensions can be connected and used in several ways:

1. Through dependencies — connecting libraries or modules via a build system (e.g., Gradle). This is the most common way to add functionality.

2. Plugins and modules — using plugins that extend the capabilities of the application or development environment.

3. Reflection and dynamic class loading — loading and using classes at runtime, allowing extensions to be connected without recompilation.

4. Integration with external services via API — expanding functionality through interaction with external systems.

Example of connecting a library in Gradle:

dependencies {
    implementation 'com.squareup.retrofit2:retrofit:2.9.0'
}

After that, you can use the library's functionality in your code.