Difference between mkdir() and mkdirs() in Java for java.io.File

java

file-handling

directory-creation

java-methods

byAnton Shumikhin·Feb 4, 2025

mkdir() creates a single directory and fails if the parent path doesn't exist. mkdirs() creates a necessary directory along with any missing parent directories.

// 'King of the Hill': this method can only make a directory if its dad is around!
new File("dir").mkdir();

// 'Superman Method': can fly up and build entire skyline!
new File("dir/subdir").mkdirs();

Understanding behavior: `mkdir()` vs `mkdirs()`

Behavior when facing non-existent directories

When playing around with directory structures, knowing how these methods react to different scenarios is crucial:

mkdir() goes like "Oops, your parent directory is missing", and just backs off, returning false.
mkdirs(), however, is the spirited adventurer. It braves paths with multiple missing directories, diligently creating each one until it either accomplishes the mission or finds an insurmountable obstacle.

Handling exceptions: We got your back

Both mkdir() and mkdirs() show power of silence. They come across a common failure case like a non-existent parent directory, shrug their shoulders and casually return false. SecurityException, however, is a different ballgame:

Security Exceptions: When the security manager does not permit directory creation, both these methods raise an alarm in the form of a SecurityException.

Cross-platform considerations: We speak all dialects

Java's mantra is to be platform-independent, and these two methods keep up the spirit:

File Separators: Use slash (/) or File.separator for worry-free code across different OS.
Cross-Platform Friendly: Both mkdir() and mkdirs() behave consistently across platforms. Directories created in one OS does not play hide and seek when accessed from another (provided correct file permissions are set).

Practical scenarios and usage: Let's get our hands dirty

When to use mkdir()

mkdir() is your buddy when:

You're adding a new directory under an established directory structure.
You have existing directories and just want to add a single directory to it.

When to use mkdirs()

mkdirs() swings into action when:

You’re aiming for a nested directory structure for your dazzling new app.
Complex paths need to be validated and created for your app's smooth functioning.

Error checking: Better safe than sorry

After calling either mkdir() or mkdirs(), it's good practice to check the return value:

if (!newDir.mkdir() && !newDir.isDirectory()) {
    // If the directory doesn't play nice, log a warning or put up the red flag
}

explain-codes / Java / Difference between mkdir() and mkdirs() in Java for java.io.File

Linked

Mkdir -p functionality in Python



How to create empty folder in java?



Node.js create folder or use existing



Deleting folders in python recursively



Equivalent of shell 'cd' command to change the working directory?



How to create new folder?



How to create a directory in Java?



Understanding behavior: vs Practical scenarios and usage: Let's get our hands dirty