How to create a directory and sub directory structure with java?

You can create all parent directories by using File.mkdirs().

File.mkdirs() - Creates the directory named by this abstract pathname, including any necessary but nonexistent parent directories. Note that if this operation fails it may have succeeded in creating some of the necessary parent directories.

You can use File.mkdir() or File.mkdirs() to create a directory. Between the two, the latter method is more tolerant and will create all intermediate directories as needed. Also, since I see that you use "\\" in your question, I would suggest using File.separator for a portable path separator string.

Starting from Java 7, you can use the java.nio.file.Files & java.nio.file.Paths classes.

Path path = Paths.get("C:\\Images\\Background\\..\\Foreground\\Necklace\\..\\Earrings\\..\\Etc");

try {
    Files.createDirectories(path);
} catch (IOException e) {
    System.err.println("Cannot create directories - " + e);
}

This is a tricky solution (because I used only one path to go to the whole structure).

If you don't like tricky solutions, you can use 4 simple paths instead:

Path p1 = Paths.get("C:\\Images\\Background");
Path p2 = Paths.get("C:\\Images\\Foreground\\Necklace");
Path p3 = Paths.get("C:\\Images\\Foreground\\Earrings");
Path p4 = Paths.get("C:\\Images\\Foreground\\Etc");

and then call the createDirectories method for all of them:

Files.createDirectories(p1);
Files.createDirectories(p2);
Files.createDirectories(p3);
Files.createDirectories(p4);