How does createNewFile internally works?

Question

createNewFile():

Atomically creates a new, empty file named by this abstract pathname if and only if a file with this name does not yet exist. The check for the existence of the file and the creation of the file if it does not exist are a single operation that is atomic with respect to all other filesystem activities that might affect the file.

How does it know if a file can be created or not ? Does it depend on the host platform ?

Answer 1

You can take a look at the OpenJDK repository. What you are looking for is this . By looking into it, you can find, that this method calls FileSystem.createFileExclusively(java.lang.String) , where FileSystem is an abstract class and the concrete instance is obtained via FileSystem.getFileSystem() which is native method, specific for different platforms.

EDIT Example for Win32 File System is here