ReadPublicKey.java

// Read all bytes from the public key file
Path path = Paths.get(publicKeyFile);
byte[] bytes = Files.readAllBytes(path);

KeyFactory keyFactory = KeyFactory.getInstance("RSA");

// Generate the public key object from bytes
X509EncodedKeySpec publicKeySpec = new X509EncodedKeySpec(bytes);
PublicKey publicKey = keyFactory.generatePublic(publicKeySpec);

// Print public key format
LOG.info(String.format("Public key format: %s", publicKey.getFormat()));