## Why is this an issue?

The classes in the `sun.*` packages are not part of the official Java API and are not intended for public use. They are internal implementation details specific to the Oracle JDK (Java Development Kit). Therefore, their availability, behavior, or compatibility is not guaranteed across different Java implementations or versions.

Since these classes are not part of the official Java API, they usually lack proper documentation and support. Finding comprehensive and up-to-date information about their usage, functionality, and potential limitations can be challenging. This lack of documentation can make it difficult to understand how to use these classes correctly.

Classes in the `sun.*` packages are often platform-dependent and can vary between different operating systems or Java Virtual Machine (JVM) implementations. Relying on these classes may lead to code that works on one platform but fails on others, limiting your code’s portability and cross-platform compatibility.

### Noncompliant code example

    import sun.misc.BASE64Encoder; // Noncompliant

## Documentation

- Sun Packages