Convert OpenSSH public key to RFC 4716 (SSH2) format

Ssh2Converter.java

/**
 * Convert OpenSSH to RFC 4716 (SSH2) format [https://tools.ietf.org/html/rfc4716]
 *
 * @author KaushikTheDeveloper
 * Created on Mar 08, 2018
 */
public class Ssh2Converter {

    private static final int MAX_LINE_LENGTH = 70;
    private static final String BEGIN_MARKER = "---- BEGIN SSH2 PUBLIC KEY ----\n";
    private static final String END_MARKER = "---- END SSH2 PUBLIC KEY ----";
    private static final String STANDARD_COMMENT = "Comment: \"2048-bit RSA, converted from OpenSSH";
    private static final String ADDITIONAL_COMMENT = " \\\nfor %s\"\n";
    private static final String NEW_LINE = "\n";

    private StringBuilder ssh2PublicKey;

    Ssh2Converter() {
        ssh2PublicKey = new StringBuilder();
    }

    /**
     * Convert Openssh to SSH2 (RFC 4716 compliant)
     *
     * @param opensshKey : the public key in openssh format
     * @return SSH2 public key
     */
    public String convert(String opensshKey) {
        try {
            ssh2PublicKey.append(BEGIN_MARKER);

            String[] opensshSplit = opensshKey.split(" ");

            appendComment(opensshSplit);
            appendHash(opensshSplit[1]);

            ssh2PublicKey.append(END_MARKER);

            return ssh2PublicKey.toString();
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    /**
     * Append the required comment
     * If comment was provided in openssh :
     * - Append Standard comment + Additional comment provided ;true
     * - Append Standard comment + close the double quotes ;false
     *
     * @param opensshSplit : openssh key split by whitespace
     */
    private void appendComment(String[] opensshSplit) {
        ssh2PublicKey.append(STANDARD_COMMENT);
        // comment is available in the openssh key
        if (opensshSplit.length == 3) {
            ssh2PublicKey.append(String.format(ADDITIONAL_COMMENT, opensshSplit[2]));
        } else {
            ssh2PublicKey.append("\"\n");
        }
    }

    /**
     * Append the hash of the OpenSSH key
     * GUIDELINE : each line in the body MUST NOT be longer than 72 8-bit bytes excluding line termination characters
     * => Split the body at 70 chars and wrap to next line
     *
     * @param hash : OpenSSH Public Key Body
     */
    private void appendHash(String hash) {
        int index = 0;
        while (index < hash.length()) {
            ssh2PublicKey.append(
                    hash.substring(index, Math.min(index + MAX_LINE_LENGTH, hash.length()))
            );
            ssh2PublicKey.append(NEW_LINE);
            index += MAX_LINE_LENGTH;
        }
    }
}


/**
 * Driver function :
 * - With comment in OpenSSH public key
 * - Without comment in OpenSSH public key
 *
 * Example key taken from [https://tools.ietf.org/html/rfc4716]
 */
class DriverFunction {
    public static void main(String[] args) {
        final String opensshKey1 = "ssh-rsa " +
                "AAAAB3NzaC1yc2EAAAABIwAAAIEA1on8gxCGJJWSRT4uOrR13mUaUk0hRf4RzxSZ1zRbYY" +
                "Fw8pfGesIFoEuVth4HKyF8k1y4mRUnYHP1XNMNMJl1JcEArC2asV8sHf6zSPVffozZ5TT4" +
                "SfsUu/iKy9lUcCfXzwre4WWZSXXcPff+EHtWshahu3WzBdnGxm5Xoi89zcE=" +
                " me@example.com";

        final String expected1 = "---- BEGIN SSH2 PUBLIC KEY ----\n" +
                "Comment: \"2048-bit RSA, converted from OpenSSH \\\n" +
                "for me@example.com\"\n" +
                "AAAAB3NzaC1yc2EAAAABIwAAAIEA1on8gxCGJJWSRT4uOrR13mUaUk0hRf4RzxSZ1zRbYY\n" +
                "Fw8pfGesIFoEuVth4HKyF8k1y4mRUnYHP1XNMNMJl1JcEArC2asV8sHf6zSPVffozZ5TT4\n" +
                "SfsUu/iKy9lUcCfXzwre4WWZSXXcPff+EHtWshahu3WzBdnGxm5Xoi89zcE=\n" +
                "---- END SSH2 PUBLIC KEY ----";

        final String result1 = new Ssh2Converter().convert(opensshKey1);

        if (!expected1.equals(result1))
            throw new RuntimeException("Assertion Failed");


        final String opensshKey2 = "ssh-rsa " +
                "AAAAB3NzaC1yc2EAAAABIwAAAIEA1on8gxCGJJWSRT4uOrR13mUaUk0hRf4RzxSZ1zRbYY" +
                "Fw8pfGesIFoEuVth4HKyF8k1y4mRUnYHP1XNMNMJl1JcEArC2asV8sHf6zSPVffozZ5TT4" +
                "SfsUu/iKy9lUcCfXzwre4WWZSXXcPff+EHtWshahu3WzBdnGxm5Xoi89zcE=";

        final String expected2 = "---- BEGIN SSH2 PUBLIC KEY ----\n" +
                "Comment: \"2048-bit RSA, converted from OpenSSH\"\n" +
                "AAAAB3NzaC1yc2EAAAABIwAAAIEA1on8gxCGJJWSRT4uOrR13mUaUk0hRf4RzxSZ1zRbYY\n" +
                "Fw8pfGesIFoEuVth4HKyF8k1y4mRUnYHP1XNMNMJl1JcEArC2asV8sHf6zSPVffozZ5TT4\n" +
                "SfsUu/iKy9lUcCfXzwre4WWZSXXcPff+EHtWshahu3WzBdnGxm5Xoi89zcE=\n" +
                "---- END SSH2 PUBLIC KEY ----";

        final String result2 = new Ssh2Converter().convert(opensshKey2);

        if (!expected2.equals(result2))
            throw new RuntimeException("Assertion Failed");
    }

}

I am going To Implement Oracles Software

If Correctthis is my eXcemtion of the license open-ssh

i forgot the p in excemption