// Creating several levels of directory all in one pop as needed.
// Note mkdirs is an instance method, so you specify the directory tree
// to create in the File constructor.
final boolean success = new File( "C:/temp/wombats" ).mkdirs();

// That is single line is equivalent to:
final File dirs = new File( "C:/temp/wombats" );

// true if created dir, false if could not create, or already created.
final boolean success = dirs.mkdirs();