How to Resolve java.io.FileNotFoundException: (Access is denied) in Java?

What causes java.io.FileNotFoundException: (Access is denied) and how can it be resolved?

List<FileItem> items = uploadHandler.parseRequest(request);
for (FileItem item : items) {
    if (!item.isFormField()) {
        File file = new File("D:/Data");
        // Attempt to save the file here
    }
}

The error `java.io.FileNotFoundException: (Access is denied)` occurs when your Java application attempts to access a file or directory without sufficient permissions. This may happen even if you believe the permissions are correctly set.

File file = new File("D:/Data/your_file.txt");
try {
    item.write(file);
} catch (Exception e) {
    e.printStackTrace();
} // Ensure you handle exceptions properly.

Causes

• The directory does not have write permissions for the Java process/user executing the program.
• The folder specified does not exist, leading to access attempts to a non-existent location.
• Java is running with insufficient privileges, such as in a restricted environment or in a non-admin mode.

Solutions

• Ensure the directory exists by checking if `D:/Data` is present in the file system.
• Verify permissions for the user running the Java application. Ensure the user has both read and write permissions on the `D:/Data` directory.
• Run your Java application in an elevated mode (as Administrator) to see if it resolves permission issues.

Mistake: Not checking if the directory exists before writing to it.

Solution: Add a check like `if (!directory.exists()) { directory.mkdir(); }` to create the directory if it doesn't exist.

Mistake: Assuming permissions are set correctly without verifying.

Solution: Use the Properties window of the folder to manually verify and adjust permissions.

Mistake: Not handling IOException properly during file operations.

Solution: Always wrap file operations in try-catch blocks to catch and log exceptions.