VirtualFile file = ... // obtain VirtualFile object FileSystem fileSystem = file.getFileSystem(); String fileSystemName = fileSystem.getProtocol();In this example, the getFileSystem() method is called on a VirtualFile object "file". The method returns a FileSystem object, which is used to obtain the protocol of the file system the VirtualFile is located in. This example could be used in a plugin for IntelliJ IDEA or a similar IDE, and makes use of the VirtualFileSystem API available in the com.intellij.openapi.vfs package. Overall, the VirtualFileSystem API in the com.intellij.openapi.vfs package is part of the IntelliJ Platform SDK, used for developing plugins for IntelliJ IDEA and other JetBrains IDEs.