Java IO & NIO 

Following example shows how keep number of files under a folder constant by deleting older files. This can be useful for the scenarios like persisting same type of events under a folder but we don't want the target folder to increase in size infinitely e.g. UI undo/redo actions, creating logs files by dates (similar to rolling behavior) etc.

Example

package com.logicbig.example;

import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.attribute.BasicFileAttributes;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.util.Comparator;
import java.util.List;
import java.util.stream.Collectors;

public class DeleteOldFilesExample {

    public static void main(String[] args) throws IOException,
            InterruptedException {
        //create test files
        Path dir = Files.createTempDirectory("test-dir-" + LocalDate.now()
                                                                    .toString());
        System.out.println("folder: " + dir);
        dir.toFile().deleteOnExit();
        for (int i = 0; i < 10; i++) {
            Path file = Files.createFile(
                    dir.resolve(Integer.toString(i + 1) + ".txt"));
            file.toFile().deleteOnExit();
            Thread.sleep(1000);
        }

        System.out.println("-- before deleting old files if more than 5 --");
        getSortedFilesByDateCreated(dir, null, true)
                .forEach(f -> System.out.println(f.toFile().getName() + " - "
                                                         + getFileCreationDateTime(
                        f.toFile())));

        System.out.println("-- deleting old files --");
        deleteOldFiles(dir, ".txt", 5);

        System.out.println("-- after deleting old files if more than 5 --");
        getSortedFilesByDateCreated(dir,
                                    null, true)
                .forEach(f -> System.out.println(f.toFile().getName() + " - "
                                                         + getFileCreationDateTime(
                        f.toFile())));
    }

    public static void deleteOldFiles(Path parentFolder,
                                      String extensionCouldBeNull,
                                      int limit) {
        List<Path> files = getSortedFilesByDateCreated(parentFolder,
                                                       extensionCouldBeNull,
                                                       false);
        if (files.size() <= limit) {
            return;
        }
        //delete recent files and keeping old files in the list
        files.subList(0, limit).clear();

        //deleting old files
        files.forEach(p -> {
            try {
                Files.delete(p);
            } catch (IOException e) {
                e.printStackTrace();
            }
        });
    }

    public static List<Path> getSortedFilesByDateCreated(
            Path parentFolder,
            String targetExtensionCouldBeNull,
            boolean ascendingOrder) {
        try {
            Comparator<Path> pathComparator =
                    Comparator.comparingLong(p -> getFileCreationEpoch(
                            (p).toFile())
                    );
            return Files.list(parentFolder)
                        .filter(Files::isRegularFile)
                        .filter(p -> targetExtensionCouldBeNull == null
                                || p.getFileName()
                                    .toString()
                                    .endsWith(
                                            targetExtensionCouldBeNull))
                        .sorted(ascendingOrder ? pathComparator :
                                        pathComparator.reversed())
                        .collect(Collectors.toList());
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    public static long getFileCreationEpoch(File file) {
        try {
            BasicFileAttributes attr = Files.readAttributes(
                    file.toPath(),
                    BasicFileAttributes.class);
            return attr.creationTime()
                       .toInstant().toEpochMilli();
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    public static LocalDateTime getFileCreationDateTime(File file) {
        try {
            BasicFileAttributes attr = Files.readAttributes(
                    file.toPath(),
                    BasicFileAttributes.class);
            return attr.creationTime()
                       .toInstant().atZone(ZoneId.systemDefault())
                       .toLocalDateTime();
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }
}

Output

folder: C:\Users\Joe\AppData\Local\Temp\test-dir-2026-07-2715310389286433546218
-- before deleting old files if more than 5 --
1.txt - 2026-07-27T20:15:43.039647
2.txt - 2026-07-27T20:15:44.042296400
3.txt - 2026-07-27T20:15:45.044458300
4.txt - 2026-07-27T20:15:46.062068400
5.txt - 2026-07-27T20:15:47.076097
6.txt - 2026-07-27T20:15:48.091569
7.txt - 2026-07-27T20:15:49.109096400
8.txt - 2026-07-27T20:15:50.125751
9.txt - 2026-07-27T20:15:51.142604200
10.txt - 2026-07-27T20:15:52.144227200
-- deleting old files --
-- after deleting old files if more than 5 --
6.txt - 2026-07-27T20:15:48.091569
7.txt - 2026-07-27T20:15:49.109096400
8.txt - 2026-07-27T20:15:50.125751
9.txt - 2026-07-27T20:15:51.142604200
10.txt - 2026-07-27T20:15:52.144227200