How do I create a directories recursively?

The code below use File.mkdirs() method to create a collection of directories recursively. It will create a directory with all its necessary parent directories.

package org.kodejava.example.io;

import java.io.File;

public class CreateDirs {
    public static void main(String[] args) {
        // Define a deep directory structures and create all the
        // directories at once.
        String directories = "D:/kodejava/a/b/c/d/e/f/g/h/i";
        File file = new File(directories);

        // The mkdirs will create folder including any necessary
        // but nonexistence parent directories. This method returns
        // true if and only if the directory was created along with
        // all necessary parent directories.
        boolean created = file.mkdirs();
        System.out.println("Directories created? " + created);
    }
}

How do I get operating system temporary directory / folder?

To get the location of temporary directory we can use the System.getProperty(String) method and pass a property key "java.io.tmpdir" as the argument to the method.

package org.kodejava.example.lang;

public class TempDirExample {
    public static void main(String[] args) {
        // This is the property name for accessing OS temporary directory
        // or folder.
        String property = "java.io.tmpdir";

        // Get the temporary directory and print it.
        String tempDir = System.getProperty(property);
        System.out.println("OS temporary directory is " + tempDir);
    }
}

How do I rename a file or directory?

package org.kodejava.example.io;

import java.io.File;
import java.io.IOException;

public class FileRenameExample {
    public static void main(String[] args) throws IOException {
        // Creates a new file called OldHouses.csv
        File oldFile = new File("OldHouses.csv");
        boolean created = oldFile.createNewFile();
        System.out.println("File created? " + created);

        // Creates the target file.
        File newFile = new File("NewHouses.csv");

        // The renameTo() method renames file or directory to a
        // new name by passing the new destination file.
        boolean renamed = oldFile.renameTo(newFile);
        System.out.println("File renamed? " + renamed);
    }
}