Java File getFreeSpace() method with examples

1. Introduction

The getFreeSpace() method returns the number of unallocated bytes in the partition. The result is not guaranteed but should be treated as a hint. It is most likely that getFreeSpace() returns the accurate value immediately after this call.

2. Method signature

public long getFreeSpace()

Parameters:

• method does not take any parameter

Returns

• long - the number or unallocated bytes on the partition

Throws

• SecurityException - if a security manager throw en error

3. Examples

3.1. The program that checks the free space of the main Linux partition under /dev/sbdb2

package com.frontbackend.java.io.examples;

import java.io.File;

public class FrontBackend {

    public static void main(String args[]) {

        try {
            File main = new File("/dev/sdb2");

            System.out.println(
                    String.format("Free space of main partition : %d bytes (%d mb)", main.getFreeSpace(), main.getFreeSpace() / 1024 / 1024));

        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

The output:

Free space of main partition : 8310472704 bytes (7925 mb)

4. Conclusion

In this short article, we presented the File.getFreeSpace() method with a simple example of how to use it in a real-life situation. This method gave the most accurate value a moment after the call, but in most cases, the result should be treated as a hint.