AccessDeniedException (File Permission)

Why This Happens

AccessDeniedException is thrown when the operating system denies the Java process access to a file or directory. This happens when the process runs as a user without the necessary read, write, or execute permissions on the target path.

The Problem

// File is read-only or owned by another user
Files.write(Path.of("/etc/config.txt"), "data".getBytes()); // AccessDeniedException

The Fix

Path path = Path.of("/tmp/config.txt"); // Write to a writable location
try {
    Files.write(path, "data".getBytes());
} catch (AccessDeniedException e) {
    System.err.println("Permission denied: " + e.getFile());
}

Step-by-Step Fix

1. 1

   Identify the file path

   Read the exception message to get the exact path that was denied.

2. 2

   Check file permissions

   Run ls -la on the file to check ownership and permissions. Verify the Java process user.

3. 3

   Fix permissions or path

   Change file permissions with chmod, change ownership with chown, or write to a directory the process has access to.