diff --git a/src/main/java/de/stklcode/jvault/connector/HTTPVaultConnector.java b/src/main/java/de/stklcode/jvault/connector/HTTPVaultConnector.java
index 7527919..20ce73f 100644
--- a/src/main/java/de/stklcode/jvault/connector/HTTPVaultConnector.java
+++ b/src/main/java/de/stklcode/jvault/connector/HTTPVaultConnector.java
@@ -79,7 +79,7 @@ public class HTTPVaultConnector implements VaultConnector {
      * @param hostname The hostname
      * @param useTLS   If TRUE, use HTTPS, otherwise HTTP
      */
-    public HTTPVaultConnector(String hostname, boolean useTLS) {
+    public HTTPVaultConnector(final String hostname, final boolean useTLS) {
         this(hostname, useTLS, null);
     }
 
@@ -90,7 +90,7 @@ public class HTTPVaultConnector implements VaultConnector {
      * @param useTLS   If TRUE, use HTTPS, otherwise HTTP
      * @param port     The port
      */
-    public HTTPVaultConnector(String hostname, boolean useTLS, Integer port) {
+    public HTTPVaultConnector(final String hostname, final boolean useTLS, final Integer port) {
         this(hostname, useTLS, port, PATH_PREFIX);
     }
 
@@ -102,7 +102,7 @@ public class HTTPVaultConnector implements VaultConnector {
      * @param port     The port
      * @param prefix   HTTP API prefix (default: /v1/)
      */
-    public HTTPVaultConnector(String hostname, boolean useTLS, Integer port, String prefix) {
+    public HTTPVaultConnector(final String hostname, final boolean useTLS, final Integer port, final String prefix) {
         this(((useTLS) ? "https" : "http") +
                 "://" + hostname +
                 ((port != null) ? ":" + port : "") +
@@ -118,7 +118,7 @@ public class HTTPVaultConnector implements VaultConnector {
      * @param prefix     HTTP API prefix (default: /v1/)
      * @param sslContext Custom SSL Context
      */
-    public HTTPVaultConnector(String hostname, boolean useTLS, Integer port, String prefix, SSLContext sslContext) {
+    public HTTPVaultConnector(final String hostname, final boolean useTLS, final Integer port, final String prefix, final SSLContext sslContext) {
         this(hostname, useTLS, port, prefix, sslContext, 0, null);
     }
 
@@ -131,7 +131,7 @@ public class HTTPVaultConnector implements VaultConnector {
      * @param prefix     HTTP API prefix (default: /v1/)
      * @param sslContext Custom SSL Context
      */
-    public HTTPVaultConnector(String hostname, boolean useTLS, Integer port, String prefix, SSLContext sslContext, int numberOfRetries, Integer timeout) {
+    public HTTPVaultConnector(final String hostname, final boolean useTLS, final Integer port, final String prefix, final SSLContext sslContext, final int numberOfRetries, final Integer timeout) {
         this(((useTLS) ? "https" : "http") +
                         "://" + hostname +
                         ((port != null) ? ":" + port : "") +
@@ -146,7 +146,7 @@ public class HTTPVaultConnector implements VaultConnector {
      *
      * @param baseURL The URL
      */
-    public HTTPVaultConnector(String baseURL) {
+    public HTTPVaultConnector(final String baseURL) {
         this(baseURL, null);
     }
 
@@ -156,7 +156,7 @@ public class HTTPVaultConnector implements VaultConnector {
      * @param baseURL    The URL
      * @param sslContext Custom SSL Context
      */
-    public HTTPVaultConnector(String baseURL, SSLContext sslContext) {
+    public HTTPVaultConnector(final String baseURL, final SSLContext sslContext) {
         this(baseURL, sslContext, 0, null);
     }
 
@@ -167,7 +167,7 @@ public class HTTPVaultConnector implements VaultConnector {
      * @param sslContext      Custom SSL Context
      * @param numberOfRetries number of retries on 5xx errors
      */
-    public HTTPVaultConnector(String baseURL, SSLContext sslContext, int numberOfRetries) {
+    public HTTPVaultConnector(final String baseURL, final SSLContext sslContext, final int numberOfRetries) {
         this(baseURL, sslContext, numberOfRetries, null);
     }
 
@@ -178,7 +178,7 @@ public class HTTPVaultConnector implements VaultConnector {
      * @param sslContext      Custom SSL Context
      * @param numberOfRetries number of retries on 5xx errors
      */
-    public HTTPVaultConnector(String baseURL, SSLContext sslContext, int numberOfRetries, Integer timeout) {
+    public HTTPVaultConnector(final String baseURL, final SSLContext sslContext, final int numberOfRetries, final Integer timeout) {
         this.baseURL = baseURL;
         this.sslContext = sslContext;
         this.retries = numberOfRetries;
@@ -187,14 +187,14 @@ public class HTTPVaultConnector implements VaultConnector {
     }
 
     @Override
-    public void resetAuth() {
+    public final void resetAuth() {
         token = null;
         tokenTTL = 0;
         authorized = false;
     }
 
     @Override
-    public SealResponse sealStatus() {
+    public final SealResponse sealStatus() {
         try {
             String response = requestGet(PATH_SEAL_STATUS, new HashMap<>());
             return jsonMapper.readValue(response, SealResponse.class);
@@ -208,7 +208,7 @@ public class HTTPVaultConnector implements VaultConnector {
     }
 
     @Override
-    public boolean seal() {
+    public final boolean seal() {
         try {
             requestPut(PATH_SEAL, new HashMap<>());
             return true;
@@ -219,7 +219,7 @@ public class HTTPVaultConnector implements VaultConnector {
     }
 
     @Override
-    public SealResponse unseal(final String key, final Boolean reset) {
+    public final SealResponse unseal(final String key, final Boolean reset) {
         Map<String, String> param = new HashMap<>();
         param.put("key", key);
         if (reset != null)
@@ -234,12 +234,12 @@ public class HTTPVaultConnector implements VaultConnector {
     }
 
     @Override
-    public boolean isAuthorized() {
+    public final boolean isAuthorized() {
         return authorized && (tokenTTL == 0 || tokenTTL >= System.currentTimeMillis());
     }
 
     @Override
-    public List<AuthBackend> getAuthBackends() throws VaultConnectorException {
+    public final List<AuthBackend> getAuthBackends() throws VaultConnectorException {
         try {
             String response = requestGet(PATH_AUTH, new HashMap<>());
             /* Parse response */
@@ -254,7 +254,7 @@ public class HTTPVaultConnector implements VaultConnector {
     }
 
     @Override
-    public TokenResponse authToken(final String token) throws VaultConnectorException {
+    public final TokenResponse authToken(final String token) throws VaultConnectorException {
         /* set token */
         this.token = token;
         this.tokenTTL = 0;
@@ -269,7 +269,7 @@ public class HTTPVaultConnector implements VaultConnector {
     }
 
     @Override
-    public AuthResponse authUserPass(final String username, final String password) throws VaultConnectorException {
+    public final AuthResponse authUserPass(final String username, final String password) throws VaultConnectorException {
         final Map<String, String> payload = new HashMap<>();
         payload.put("password", password);
         return queryAuth(PATH_AUTH_USERPASS + username, payload);
@@ -277,7 +277,7 @@ public class HTTPVaultConnector implements VaultConnector {
 
     @Override
     @Deprecated
-    public AuthResponse authAppId(final String appID, final String userID) throws VaultConnectorException {
+    public final AuthResponse authAppId(final String appID, final String userID) throws VaultConnectorException {
         final Map<String, String> payload = new HashMap<>();
         payload.put("app_id", appID);
         payload.put("user_id", userID);
@@ -285,7 +285,7 @@ public class HTTPVaultConnector implements VaultConnector {
     }
 
     @Override
-    public AuthResponse authAppRole(final String roleID, final String secretID) throws VaultConnectorException {
+    public final AuthResponse authAppRole(final String roleID, final String secretID) throws VaultConnectorException {
         final Map<String, String> payload = new HashMap<>();
         payload.put("role_id", roleID);
         if (secretID != null)
@@ -319,7 +319,7 @@ public class HTTPVaultConnector implements VaultConnector {
 
     @Override
     @Deprecated
-    public boolean registerAppId(final String appID, final String policy, final String displayName) throws VaultConnectorException {
+    public final boolean registerAppId(final String appID, final String policy, final String displayName) throws VaultConnectorException {
         if (!isAuthorized())
             throw new AuthorizationRequiredException();
         Map<String, String> payload = new HashMap<>();
@@ -335,7 +335,7 @@ public class HTTPVaultConnector implements VaultConnector {
 
     @Override
     @Deprecated
-    public boolean registerUserId(final String appID, final String userID) throws VaultConnectorException {
+    public final boolean registerUserId(final String appID, final String userID) throws VaultConnectorException {
         if (!isAuthorized())
             throw new AuthorizationRequiredException();
         Map<String, String> payload = new HashMap<>();
@@ -349,7 +349,7 @@ public class HTTPVaultConnector implements VaultConnector {
     }
 
     @Override
-    public boolean createAppRole(final AppRole role) throws VaultConnectorException {
+    public final boolean createAppRole(final AppRole role) throws VaultConnectorException {
         if (!isAuthorized())
             throw new AuthorizationRequiredException();
         /* Get response */
@@ -363,7 +363,7 @@ public class HTTPVaultConnector implements VaultConnector {
     }
 
     @Override
-    public AppRoleResponse lookupAppRole(final String roleName) throws VaultConnectorException {
+    public final AppRoleResponse lookupAppRole(final String roleName) throws VaultConnectorException {
         if (!isAuthorized())
             throw new AuthorizationRequiredException();
         /* Request HTTP response and parse Secret */
@@ -379,7 +379,7 @@ public class HTTPVaultConnector implements VaultConnector {
     }
 
     @Override
-    public boolean deleteAppRole(String roleName) throws VaultConnectorException {
+    public final boolean deleteAppRole(final String roleName) throws VaultConnectorException {
         if (!isAuthorized())
             throw new AuthorizationRequiredException();
 
@@ -394,7 +394,7 @@ public class HTTPVaultConnector implements VaultConnector {
     }
 
     @Override
-    public String getAppRoleID(final String roleName) throws VaultConnectorException {
+    public final String getAppRoleID(final String roleName) throws VaultConnectorException {
         if (!isAuthorized())
             throw new AuthorizationRequiredException();
         /* Request HTTP response and parse Secret */
@@ -410,7 +410,7 @@ public class HTTPVaultConnector implements VaultConnector {
     }
 
     @Override
-    public boolean setAppRoleID(final String roleName, final String roleID) throws VaultConnectorException {
+    public final boolean setAppRoleID(final String roleName, final String roleID) throws VaultConnectorException {
         if (!isAuthorized())
             throw new AuthorizationRequiredException();
         /* Request HTTP response and parse Secret */
@@ -424,7 +424,7 @@ public class HTTPVaultConnector implements VaultConnector {
     }
 
     @Override
-    public AppRoleSecretResponse createAppRoleSecret(final String roleName, final AppRoleSecret secret) throws VaultConnectorException {
+    public final AppRoleSecretResponse createAppRoleSecret(final String roleName, final AppRoleSecret secret) throws VaultConnectorException {
         if (!isAuthorized())
             throw new AuthorizationRequiredException();
         /* Get response */
@@ -443,7 +443,7 @@ public class HTTPVaultConnector implements VaultConnector {
     }
 
     @Override
-    public AppRoleSecretResponse lookupAppRoleSecret(final String roleName, final String secretID) throws VaultConnectorException {
+    public final AppRoleSecretResponse lookupAppRoleSecret(final String roleName, final String secretID) throws VaultConnectorException {
         if (!isAuthorized())
             throw new AuthorizationRequiredException();
         /* Request HTTP response and parse Secret */
@@ -456,7 +456,7 @@ public class HTTPVaultConnector implements VaultConnector {
     }
 
     @Override
-    public boolean destroyAppRoleSecret(final String roleName, final String secretID) throws VaultConnectorException {
+    public final boolean destroyAppRoleSecret(final String roleName, final String secretID) throws VaultConnectorException {
         if (!isAuthorized())
             throw new AuthorizationRequiredException();
 
@@ -471,7 +471,7 @@ public class HTTPVaultConnector implements VaultConnector {
     }
 
     @Override
-    public List<String> listAppRoles() throws VaultConnectorException {
+    public final List<String> listAppRoles() throws VaultConnectorException {
         if (!isAuthorized())
             throw new AuthorizationRequiredException();
 
@@ -488,7 +488,7 @@ public class HTTPVaultConnector implements VaultConnector {
     }
 
     @Override
-    public List<String> listAppRoleSecretss(final String roleName) throws VaultConnectorException {
+    public final List<String> listAppRoleSecretss(final String roleName) throws VaultConnectorException {
         if (!isAuthorized())
             throw new AuthorizationRequiredException();
 
@@ -505,7 +505,7 @@ public class HTTPVaultConnector implements VaultConnector {
     }
 
     @Override
-    public SecretResponse read(final String key) throws VaultConnectorException {
+    public final SecretResponse read(final String key) throws VaultConnectorException {
         if (!isAuthorized())
             throw new AuthorizationRequiredException();
         /* Request HTTP response and parse Secret */
@@ -521,7 +521,7 @@ public class HTTPVaultConnector implements VaultConnector {
     }
 
     @Override
-    public List<String> list(final String path) throws VaultConnectorException {
+    public final List<String> list(final String path) throws VaultConnectorException {
         if (!isAuthorized())
             throw new AuthorizationRequiredException();
 
@@ -537,7 +537,7 @@ public class HTTPVaultConnector implements VaultConnector {
         }
     }
 
-    public void write(final String key, final Map<String, Object> data) throws VaultConnectorException {
+    public final void write(final String key, final Map<String, Object> data) throws VaultConnectorException {
         if (!isAuthorized())
             throw new AuthorizationRequiredException();
 
@@ -549,7 +549,7 @@ public class HTTPVaultConnector implements VaultConnector {
     }
 
     @Override
-    public void delete(String key) throws VaultConnectorException {
+    public final void delete(final String key) throws VaultConnectorException {
         if (!isAuthorized())
             throw new AuthorizationRequiredException();
 
@@ -562,7 +562,7 @@ public class HTTPVaultConnector implements VaultConnector {
     }
 
     @Override
-    public void revoke(String leaseID) throws VaultConnectorException {
+    public final void revoke(final String leaseID) throws VaultConnectorException {
         if (!isAuthorized())
             throw new AuthorizationRequiredException();
 
@@ -575,7 +575,7 @@ public class HTTPVaultConnector implements VaultConnector {
     }
 
     @Override
-    public SecretResponse renew(String leaseID, Integer increment) throws VaultConnectorException {
+    public final SecretResponse renew(final String leaseID, final Integer increment) throws VaultConnectorException {
         if (!isAuthorized())
             throw new AuthorizationRequiredException();
 
@@ -594,24 +594,24 @@ public class HTTPVaultConnector implements VaultConnector {
     }
 
     @Override
-    public AuthResponse createToken(final Token token) throws VaultConnectorException {
+    public final AuthResponse createToken(final Token token) throws VaultConnectorException {
         return createTokenInternal(token, PATH_TOKEN + PATH_CREATE);
     }
 
     @Override
-    public AuthResponse createToken(final Token token, boolean orphan) throws VaultConnectorException {
+    public final AuthResponse createToken(final Token token, final boolean orphan) throws VaultConnectorException {
         return createTokenInternal(token, PATH_TOKEN + PATH_CREATE_ORPHAN);
     }
 
     @Override
-    public AuthResponse createToken(final Token token, final String role) throws VaultConnectorException {
+    public final AuthResponse createToken(final Token token, final String role) throws VaultConnectorException {
         if (role == null || role.isEmpty())
             throw new InvalidRequestException("No role name specified.");
         return createTokenInternal(token, PATH_TOKEN + PATH_CREATE + "/" + role);
     }
 
     @Override
-    public void close() {
+    public final void close() {
         authorized = false;
         token = null;
         tokenTTL = 0;
@@ -642,7 +642,7 @@ public class HTTPVaultConnector implements VaultConnector {
     }
 
     @Override
-    public TokenResponse lookupToken(final String token) throws VaultConnectorException {
+    public final TokenResponse lookupToken(final String token) throws VaultConnectorException {
         if (!isAuthorized())
             throw new AuthorizationRequiredException();
         /* Request HTTP response and parse Secret */
@@ -762,7 +762,7 @@ public class HTTPVaultConnector implements VaultConnector {
      * @return HTTP response
      * @throws VaultConnectorException on connection error
      */
-    private String request(HttpRequestBase base, int retries) throws VaultConnectorException {
+    private String request(final HttpRequestBase base, final int retries) throws VaultConnectorException {
         /* Set JSON Header */
         base.addHeader("accept", "application/json");
 
diff --git a/src/main/java/de/stklcode/jvault/connector/exception/ConnectionException.java b/src/main/java/de/stklcode/jvault/connector/exception/ConnectionException.java
index bcfd071..612f1e9 100644
--- a/src/main/java/de/stklcode/jvault/connector/exception/ConnectionException.java
+++ b/src/main/java/de/stklcode/jvault/connector/exception/ConnectionException.java
@@ -26,15 +26,15 @@ public class ConnectionException extends VaultConnectorException {
     public ConnectionException() {
     }
 
-    public ConnectionException(String message) {
+    public ConnectionException(final String message) {
         super(message);
     }
 
-    public ConnectionException(Throwable cause) {
+    public ConnectionException(final Throwable cause) {
         super(cause);
     }
 
-    public ConnectionException(String message, Throwable cause) {
+    public ConnectionException(final String message, final Throwable cause) {
         super(message, cause);
     }
 }
diff --git a/src/main/java/de/stklcode/jvault/connector/exception/InvalidRequestException.java b/src/main/java/de/stklcode/jvault/connector/exception/InvalidRequestException.java
index d71b984..6222f98 100644
--- a/src/main/java/de/stklcode/jvault/connector/exception/InvalidRequestException.java
+++ b/src/main/java/de/stklcode/jvault/connector/exception/InvalidRequestException.java
@@ -26,15 +26,15 @@ public class InvalidRequestException extends VaultConnectorException {
     public InvalidRequestException() {
     }
 
-    public InvalidRequestException(String message) {
+    public InvalidRequestException(final String message) {
         super(message);
     }
 
-    public InvalidRequestException(Throwable cause) {
+    public InvalidRequestException(final Throwable cause) {
         super(cause);
     }
 
-    public InvalidRequestException(String message, Throwable cause) {
+    public InvalidRequestException(final String message, final Throwable cause) {
         super(message, cause);
     }
 }
diff --git a/src/main/java/de/stklcode/jvault/connector/exception/InvalidResponseException.java b/src/main/java/de/stklcode/jvault/connector/exception/InvalidResponseException.java
index bc0bc59..803f1fb 100644
--- a/src/main/java/de/stklcode/jvault/connector/exception/InvalidResponseException.java
+++ b/src/main/java/de/stklcode/jvault/connector/exception/InvalidResponseException.java
@@ -23,31 +23,31 @@ package de.stklcode.jvault.connector.exception;
  * @author  Stefan Kalscheuer
  * @since   0.1
  */
-public class InvalidResponseException extends VaultConnectorException {
+public final class InvalidResponseException extends VaultConnectorException {
     private Integer statusCode;
     private String response;
 
     public InvalidResponseException() {
     }
 
-    public InvalidResponseException(String message) {
+    public InvalidResponseException(final String message) {
         super(message);
     }
 
-    public InvalidResponseException(Throwable cause) {
+    public InvalidResponseException(final Throwable cause) {
         super(cause);
     }
 
-    public InvalidResponseException(String message, Throwable cause) {
+    public InvalidResponseException(final String message, final Throwable cause) {
         super(message, cause);
     }
 
-    public InvalidResponseException withStatusCode(Integer statusCode) {
+    public InvalidResponseException withStatusCode(final Integer statusCode) {
         this.statusCode = statusCode;
         return this;
     }
 
-    public InvalidResponseException withResponse(String response) {
+    public InvalidResponseException withResponse(final String response) {
         this.response = response;
         return this;
     }
diff --git a/src/main/java/de/stklcode/jvault/connector/exception/PermissionDeniedException.java b/src/main/java/de/stklcode/jvault/connector/exception/PermissionDeniedException.java
index 2a23fcb..82140d6 100644
--- a/src/main/java/de/stklcode/jvault/connector/exception/PermissionDeniedException.java
+++ b/src/main/java/de/stklcode/jvault/connector/exception/PermissionDeniedException.java
@@ -27,15 +27,15 @@ public class PermissionDeniedException extends VaultConnectorException {
         super("Permission denied");
     }
 
-    public PermissionDeniedException(String message) {
+    public PermissionDeniedException(final String message) {
         super(message);
     }
 
-    public PermissionDeniedException(Throwable cause) {
+    public PermissionDeniedException(final Throwable cause) {
         super(cause);
     }
 
-    public PermissionDeniedException(String message, Throwable cause) {
+    public PermissionDeniedException(final String message, final Throwable cause) {
         super(message, cause);
     }
 }
diff --git a/src/main/java/de/stklcode/jvault/connector/exception/TlsException.java b/src/main/java/de/stklcode/jvault/connector/exception/TlsException.java
index 7cfddeb..53ebefd 100644
--- a/src/main/java/de/stklcode/jvault/connector/exception/TlsException.java
+++ b/src/main/java/de/stklcode/jvault/connector/exception/TlsException.java
@@ -26,15 +26,15 @@ public class TlsException extends VaultConnectorException {
     public TlsException() {
     }
 
-    public TlsException(String message) {
+    public TlsException(final String message) {
         super(message);
     }
 
-    public TlsException(Throwable cause) {
+    public TlsException(final Throwable cause) {
         super(cause);
     }
 
-    public TlsException(String message, Throwable cause) {
+    public TlsException(final String message, final Throwable cause) {
         super(message, cause);
     }
 }
diff --git a/src/main/java/de/stklcode/jvault/connector/exception/VaultConnectorException.java b/src/main/java/de/stklcode/jvault/connector/exception/VaultConnectorException.java
index b79f10b..f4ca582 100644
--- a/src/main/java/de/stklcode/jvault/connector/exception/VaultConnectorException.java
+++ b/src/main/java/de/stklcode/jvault/connector/exception/VaultConnectorException.java
@@ -26,15 +26,15 @@ public abstract class VaultConnectorException extends Exception {
     public VaultConnectorException() {
     }
 
-    public VaultConnectorException(String message) {
+    public VaultConnectorException(final String message) {
         super(message);
     }
 
-    public VaultConnectorException(Throwable cause) {
+    public VaultConnectorException(final Throwable cause) {
         super(cause);
     }
 
-    public VaultConnectorException(String message, Throwable cause) {
+    public VaultConnectorException(final String message, final Throwable cause) {
         super(message, cause);
     }
 }
diff --git a/src/main/java/de/stklcode/jvault/connector/factory/HTTPVaultConnectorFactory.java b/src/main/java/de/stklcode/jvault/connector/factory/HTTPVaultConnectorFactory.java
index 6e6fb38..56e2328 100644
--- a/src/main/java/de/stklcode/jvault/connector/factory/HTTPVaultConnectorFactory.java
+++ b/src/main/java/de/stklcode/jvault/connector/factory/HTTPVaultConnectorFactory.java
@@ -43,7 +43,7 @@ import java.security.cert.X509Certificate;
  * @author Stefan Kalscheuer
  * @since 0.1
  */
-public class HTTPVaultConnectorFactory extends VaultConnectorFactory {
+public final class HTTPVaultConnectorFactory extends VaultConnectorFactory {
     private static final String ENV_VAULT_ADDR = "VAULT_ADDR";
     private static final String ENV_VAULT_CACERT = "VAULT_CACERT";
     private static final String ENV_VAULT_TOKEN = "VAULT_TOKEN";
@@ -82,7 +82,7 @@ public class HTTPVaultConnectorFactory extends VaultConnectorFactory {
      * @param host Hostname or IP address
      * @return self
      */
-    public HTTPVaultConnectorFactory withHost(String host) {
+    public HTTPVaultConnectorFactory withHost(final String host) {
         this.host = host;
         return this;
     }
@@ -93,7 +93,7 @@ public class HTTPVaultConnectorFactory extends VaultConnectorFactory {
      * @param port Vault TCP port
      * @return self
      */
-    public HTTPVaultConnectorFactory withPort(Integer port) {
+    public HTTPVaultConnectorFactory withPort(final Integer port) {
         this.port = port;
         return this;
     }
@@ -104,7 +104,7 @@ public class HTTPVaultConnectorFactory extends VaultConnectorFactory {
      * @param useTLS use TLS or not
      * @return self
      */
-    public HTTPVaultConnectorFactory withTLS(boolean useTLS) {
+    public HTTPVaultConnectorFactory withTLS(final boolean useTLS) {
         this.tls = useTLS;
         return this;
     }
@@ -133,7 +133,7 @@ public class HTTPVaultConnectorFactory extends VaultConnectorFactory {
      * @param prefix Vault API prefix (default: "/v1/"
      * @return self
      */
-    public HTTPVaultConnectorFactory withPrefix(String prefix) {
+    public HTTPVaultConnectorFactory withPrefix(final String prefix) {
         this.prefix = prefix;
         return this;
     }
@@ -146,7 +146,7 @@ public class HTTPVaultConnectorFactory extends VaultConnectorFactory {
      * @throws VaultConnectorException on error
      * @since 0.4.0
      */
-    public HTTPVaultConnectorFactory withTrustedCA(Path cert) throws VaultConnectorException {
+    public HTTPVaultConnectorFactory withTrustedCA(final Path cert) throws VaultConnectorException {
         if (cert != null)
             return withSslContext(createSslContext(cert));
         return this;
@@ -160,7 +160,7 @@ public class HTTPVaultConnectorFactory extends VaultConnectorFactory {
      * @return self
      * @since 0.4.0
      */
-    public HTTPVaultConnectorFactory withSslContext(SSLContext sslContext) {
+    public HTTPVaultConnectorFactory withSslContext(final SSLContext sslContext) {
         this.sslContext = sslContext;
         return this;
     }
@@ -172,7 +172,7 @@ public class HTTPVaultConnectorFactory extends VaultConnectorFactory {
      * @return self
      * @since 0.6.0
      */
-    public HTTPVaultConnectorFactory withToken(String token) throws VaultConnectorException {
+    public HTTPVaultConnectorFactory withToken(final String token) throws VaultConnectorException {
         this.token = token;
         return this;
     }
@@ -221,7 +221,7 @@ public class HTTPVaultConnectorFactory extends VaultConnectorFactory {
      * @return self
      * @since 0.6.0
      */
-    public HTTPVaultConnectorFactory withNumberOfRetries(int numberOfRetries) {
+    public HTTPVaultConnectorFactory withNumberOfRetries(final int numberOfRetries) {
         this.numberOfRetries = numberOfRetries;
         return this;
     }
@@ -233,7 +233,7 @@ public class HTTPVaultConnectorFactory extends VaultConnectorFactory {
      * @return self
      * @since 0.6.0
      */
-    public HTTPVaultConnectorFactory withTimeout(int milliseconds) {
+    public HTTPVaultConnectorFactory withTimeout(final int milliseconds) {
         this.timeout = milliseconds;
         return this;
     }
@@ -260,7 +260,7 @@ public class HTTPVaultConnectorFactory extends VaultConnectorFactory {
      * @throws TlsException on errors
      * @since 0.4.0
      */
-    private SSLContext createSslContext(Path trustedCert) throws TlsException {
+    private SSLContext createSslContext(final Path trustedCert) throws TlsException {
         try {
             SSLContext context = SSLContext.getInstance("TLS");
             context.init(null, createTrustManager(trustedCert), new SecureRandom());
@@ -278,7 +278,7 @@ public class HTTPVaultConnectorFactory extends VaultConnectorFactory {
      * @throws TlsException on error
      * @since 0.4.0
      */
-    private TrustManager[] createTrustManager(Path trustedCert) throws TlsException {
+    private TrustManager[] createTrustManager(final Path trustedCert) throws TlsException {
         try {
             /* Create Keystore with trusted certificate */
             KeyStore keyStore = KeyStore.getInstance(KeyStore.getDefaultType());
@@ -301,7 +301,7 @@ public class HTTPVaultConnectorFactory extends VaultConnectorFactory {
      * @throws TlsException on error
      * @since 0.4.0
      */
-    private X509Certificate certificateFromFile(Path certFile) throws TlsException {
+    private X509Certificate certificateFromFile(final Path certFile) throws TlsException {
         try (InputStream is = Files.newInputStream(certFile)) {
             return (X509Certificate) CertificateFactory.getInstance("X.509").generateCertificate(is);
         } catch (IOException | CertificateException e) {
diff --git a/src/main/java/de/stklcode/jvault/connector/model/AppRole.java b/src/main/java/de/stklcode/jvault/connector/model/AppRole.java
index e8fa519..04b95e1 100644
--- a/src/main/java/de/stklcode/jvault/connector/model/AppRole.java
+++ b/src/main/java/de/stklcode/jvault/connector/model/AppRole.java
@@ -28,7 +28,7 @@ import java.util.List;
  * @since 0.4.0
  */
 @JsonIgnoreProperties(ignoreUnknown = true)
-public class AppRole {
+public final class AppRole {
     @JsonProperty("role_name")
     private String name;
 
@@ -68,7 +68,9 @@ public class AppRole {
 
     }
 
-    public AppRole(String name, String id, Boolean bindSecretId, List<String> boundCidrList, List<String> policies, Integer secretIdNumUses, Integer secretIdTtl, Integer tokenTtl, Integer tokenMaxTtl, Integer period) {
+    public AppRole(final String name, final String id, final Boolean bindSecretId, final List<String> boundCidrList,
+                   final List<String> policies, final Integer secretIdNumUses, final Integer secretIdTtl,
+                   final Integer tokenTtl, final Integer tokenMaxTtl, final Integer period) {
         this.name = name;
         this.id = id;
         this.bindSecretId = bindSecretId;
@@ -98,7 +100,7 @@ public class AppRole {
     }
 
     @JsonSetter("bound_cidr_list")
-    public void setBoundCidrList(List<String> boundCidrList) {
+    public void setBoundCidrList(final List<String> boundCidrList) {
         this.boundCidrList = boundCidrList;
     }
 
@@ -115,7 +117,7 @@ public class AppRole {
     }
 
     @JsonSetter("policies")
-    public void setPolicies(List<String> policies) {
+    public void setPolicies(final List<String> policies) {
         this.policies = policies;
     }
 
diff --git a/src/main/java/de/stklcode/jvault/connector/model/AppRoleBuilder.java b/src/main/java/de/stklcode/jvault/connector/model/AppRoleBuilder.java
index 2c7e51d..fa71760 100644
--- a/src/main/java/de/stklcode/jvault/connector/model/AppRoleBuilder.java
+++ b/src/main/java/de/stklcode/jvault/connector/model/AppRoleBuilder.java
@@ -25,7 +25,7 @@ import java.util.List;
  * @author Stefan Kalscheuer
  * @since 0.4.0
  */
-public class AppRoleBuilder {
+public final class AppRoleBuilder {
     private String name;
     private String id;
     private Boolean bindSecretId;
@@ -37,7 +37,7 @@ public class AppRoleBuilder {
     private Integer tokenMaxTtl;
     private Integer period;
 
-    public AppRoleBuilder(String name) {
+    public AppRoleBuilder(final String name) {
         this.name = name;
     }
 
diff --git a/src/main/java/de/stklcode/jvault/connector/model/AppRoleSecret.java b/src/main/java/de/stklcode/jvault/connector/model/AppRoleSecret.java
index 4bc1d48..9eee0e2 100644
--- a/src/main/java/de/stklcode/jvault/connector/model/AppRoleSecret.java
+++ b/src/main/java/de/stklcode/jvault/connector/model/AppRoleSecret.java
@@ -29,7 +29,7 @@ import java.util.Map;
  * @since 0.4.0
  */
 @JsonIgnoreProperties(ignoreUnknown = true)
-public class AppRoleSecret {
+public final class AppRoleSecret {
     @JsonProperty("secret_id")
     @JsonInclude(JsonInclude.Include.NON_NULL)
     private String id;
@@ -62,11 +62,11 @@ public class AppRoleSecret {
 
     }
 
-    public AppRoleSecret(String id) {
+    public AppRoleSecret(final String id) {
         this.id = id;
     }
 
-    public AppRoleSecret(String id, Map<String, Object> metadata, List<String> cidrList) {
+    public AppRoleSecret(final String id, final Map<String, Object> metadata, final List<String> cidrList) {
         this.id = id;
         this.metadata = metadata;
         this.cidrList = cidrList;
@@ -89,7 +89,7 @@ public class AppRoleSecret {
     }
 
     @JsonSetter("cidr_list")
-    public void setCidrList(List<String> cidrList) {
+    public void setCidrList(final List<String> cidrList) {
         this.cidrList = cidrList;
     }
 
diff --git a/src/main/java/de/stklcode/jvault/connector/model/AuthBackend.java b/src/main/java/de/stklcode/jvault/connector/model/AuthBackend.java
index 283ac6c..160bdbe 100644
--- a/src/main/java/de/stklcode/jvault/connector/model/AuthBackend.java
+++ b/src/main/java/de/stklcode/jvault/connector/model/AuthBackend.java
@@ -31,11 +31,11 @@ public enum AuthBackend {
 
     private final String type;
 
-    AuthBackend(String type) {
+    AuthBackend(final String type) {
         this.type = type;
     }
 
-    public static AuthBackend forType(String type) {
+    public static AuthBackend forType(final String type) {
         for (AuthBackend v : values())
             if (v.type.equalsIgnoreCase(type))
                 return v;
diff --git a/src/main/java/de/stklcode/jvault/connector/model/Token.java b/src/main/java/de/stklcode/jvault/connector/model/Token.java
index be9a843..e672ba1 100644
--- a/src/main/java/de/stklcode/jvault/connector/model/Token.java
+++ b/src/main/java/de/stklcode/jvault/connector/model/Token.java
@@ -30,7 +30,7 @@ import java.util.Map;
  * @since 0.4.0
  */
 @JsonIgnoreProperties(ignoreUnknown = true)
-public class Token {
+public final class Token {
     @JsonProperty("id")
     @JsonInclude(JsonInclude.Include.NON_NULL)
     private String id;
@@ -67,7 +67,9 @@ public class Token {
     @JsonInclude(JsonInclude.Include.NON_NULL)
     private Boolean renewable;
 
-    public Token(String id, String displayName, Boolean noParent, Boolean noDefaultPolicy, Integer ttl, Integer numUses, List<String> policies, Map<String, String> meta, Boolean renewable) {
+    public Token(final String id, final String displayName, final Boolean noParent, final Boolean noDefaultPolicy,
+                 final Integer ttl, final Integer numUses, final List<String> policies, final Map<String, String> meta,
+                 final Boolean renewable) {
         this.id = id;
         this.displayName = displayName;
         this.ttl = ttl;
diff --git a/src/main/java/de/stklcode/jvault/connector/model/TokenBuilder.java b/src/main/java/de/stklcode/jvault/connector/model/TokenBuilder.java
index 70f15c5..3ed5380 100644
--- a/src/main/java/de/stklcode/jvault/connector/model/TokenBuilder.java
+++ b/src/main/java/de/stklcode/jvault/connector/model/TokenBuilder.java
@@ -26,7 +26,7 @@ import java.util.*;
  * @author  Stefan Kalscheuer
  * @since 0.4.0
  */
-public class TokenBuilder {
+public final class TokenBuilder {
     private String id;
     private String displayName;
     private Boolean noParent;
diff --git a/src/main/java/de/stklcode/jvault/connector/model/response/AppRoleResponse.java b/src/main/java/de/stklcode/jvault/connector/model/response/AppRoleResponse.java
index 891dc04..899b556 100644
--- a/src/main/java/de/stklcode/jvault/connector/model/response/AppRoleResponse.java
+++ b/src/main/java/de/stklcode/jvault/connector/model/response/AppRoleResponse.java
@@ -33,11 +33,11 @@ import java.util.stream.Collectors;
  * @since   0.4.0
  */
 @JsonIgnoreProperties(ignoreUnknown = true)
-public class AppRoleResponse extends VaultDataResponse {
+public final class AppRoleResponse extends VaultDataResponse {
     private AppRole role;
 
     @Override
-    public void setData(Map<String, Object> data) throws InvalidResponseException {
+    public void setData(final Map<String, Object> data) throws InvalidResponseException {
         ObjectMapper mapper = new ObjectMapper();
         try {
             /* null empty strings on list objects */
diff --git a/src/main/java/de/stklcode/jvault/connector/model/response/AppRoleSecretResponse.java b/src/main/java/de/stklcode/jvault/connector/model/response/AppRoleSecretResponse.java
index 80e930f..24d0066 100644
--- a/src/main/java/de/stklcode/jvault/connector/model/response/AppRoleSecretResponse.java
+++ b/src/main/java/de/stklcode/jvault/connector/model/response/AppRoleSecretResponse.java
@@ -33,11 +33,11 @@ import java.util.Map;
  * @since   0.4.0
  */
 @JsonIgnoreProperties(ignoreUnknown = true)
-public class AppRoleSecretResponse extends VaultDataResponse {
+public final class AppRoleSecretResponse extends VaultDataResponse {
     private AppRoleSecret secret;
 
     @Override
-    public void setData(Map<String, Object> data) throws InvalidResponseException {
+    public void setData(final Map<String, Object> data) throws InvalidResponseException {
         ObjectMapper mapper = new ObjectMapper();
         try {
             /* null empty strings on list objects */
diff --git a/src/main/java/de/stklcode/jvault/connector/model/response/AuthMethodsResponse.java b/src/main/java/de/stklcode/jvault/connector/model/response/AuthMethodsResponse.java
index 0c56a35..88532d4 100644
--- a/src/main/java/de/stklcode/jvault/connector/model/response/AuthMethodsResponse.java
+++ b/src/main/java/de/stklcode/jvault/connector/model/response/AuthMethodsResponse.java
@@ -32,7 +32,7 @@ import java.util.Map;
  * @since   0.1
  */
 @JsonIgnoreProperties(ignoreUnknown = true)
-public class AuthMethodsResponse extends VaultDataResponse {
+public final class AuthMethodsResponse extends VaultDataResponse {
     private Map<String, AuthMethod> supportedMethods;
 
     public AuthMethodsResponse() {
@@ -40,7 +40,7 @@ public class AuthMethodsResponse extends VaultDataResponse {
     }
 
     @Override
-    public void setData(Map<String, Object> data) throws InvalidResponseException {
+    public void setData(final Map<String, Object> data) throws InvalidResponseException {
         ObjectMapper mapper = new ObjectMapper();
         for (String path : data.keySet()) {
             try {
diff --git a/src/main/java/de/stklcode/jvault/connector/model/response/AuthResponse.java b/src/main/java/de/stklcode/jvault/connector/model/response/AuthResponse.java
index e334965..8afcb76 100644
--- a/src/main/java/de/stklcode/jvault/connector/model/response/AuthResponse.java
+++ b/src/main/java/de/stklcode/jvault/connector/model/response/AuthResponse.java
@@ -32,13 +32,13 @@ import java.util.Map;
  * @since   0.1
  */
 @JsonIgnoreProperties(ignoreUnknown = true)
-public class AuthResponse extends VaultDataResponse {
+public final class AuthResponse extends VaultDataResponse {
     private Map<String, Object> data;
 
     private AuthData auth;
 
     @JsonProperty("auth")
-    public void setAuth(Map<String, Object> auth) throws InvalidResponseException {
+    public void setAuth(final Map<String, Object> auth) throws InvalidResponseException {
         ObjectMapper mapper = new ObjectMapper();
         try {
             this.auth = mapper.readValue(mapper.writeValueAsString(auth), AuthData.class);
@@ -49,7 +49,7 @@ public class AuthResponse extends VaultDataResponse {
     }
 
     @Override
-    public void setData(Map<String, Object> data) {
+    public void setData(final Map<String, Object> data) {
         this.data = data;
     }
 
diff --git a/src/main/java/de/stklcode/jvault/connector/model/response/CredentialsResponse.java b/src/main/java/de/stklcode/jvault/connector/model/response/CredentialsResponse.java
index 7e35f5c..5482592 100644
--- a/src/main/java/de/stklcode/jvault/connector/model/response/CredentialsResponse.java
+++ b/src/main/java/de/stklcode/jvault/connector/model/response/CredentialsResponse.java
@@ -32,7 +32,7 @@ import java.util.Map;
  * @since   0.5.0
  */
 @JsonIgnoreProperties(ignoreUnknown = true)
-public class CredentialsResponse extends SecretResponse {
+public final class CredentialsResponse extends SecretResponse {
 
     public String getUsername() {
         if (get("username") != null)
diff --git a/src/main/java/de/stklcode/jvault/connector/model/response/ErrorResponse.java b/src/main/java/de/stklcode/jvault/connector/model/response/ErrorResponse.java
index 8742591..e86a6c4 100644
--- a/src/main/java/de/stklcode/jvault/connector/model/response/ErrorResponse.java
+++ b/src/main/java/de/stklcode/jvault/connector/model/response/ErrorResponse.java
@@ -28,7 +28,7 @@ import java.util.List;
  * @since   0.1
  */
 @JsonIgnoreProperties(ignoreUnknown = true)
-public class ErrorResponse implements VaultResponse {
+public final class ErrorResponse implements VaultResponse {
     @JsonProperty("errors")
     private List<String> errors;
 
diff --git a/src/main/java/de/stklcode/jvault/connector/model/response/HelpResponse.java b/src/main/java/de/stklcode/jvault/connector/model/response/HelpResponse.java
index 4e05676..78c69b9 100644
--- a/src/main/java/de/stklcode/jvault/connector/model/response/HelpResponse.java
+++ b/src/main/java/de/stklcode/jvault/connector/model/response/HelpResponse.java
@@ -26,7 +26,7 @@ import com.fasterxml.jackson.annotation.JsonProperty;
  * @since   0.1
  */
 @JsonIgnoreProperties(ignoreUnknown = true)
-public class HelpResponse implements VaultResponse {
+public final class HelpResponse implements VaultResponse {
     @JsonProperty("help")
     private String help;
 
diff --git a/src/main/java/de/stklcode/jvault/connector/model/response/RawDataResponse.java b/src/main/java/de/stklcode/jvault/connector/model/response/RawDataResponse.java
index dfbc420..0aadfe0 100644
--- a/src/main/java/de/stklcode/jvault/connector/model/response/RawDataResponse.java
+++ b/src/main/java/de/stklcode/jvault/connector/model/response/RawDataResponse.java
@@ -27,11 +27,11 @@ import java.util.Map;
  * @since   0.4.0
  */
 @JsonIgnoreProperties(ignoreUnknown = true)
-public class RawDataResponse extends VaultDataResponse {
+public final class RawDataResponse extends VaultDataResponse {
     private Map<String, Object> data;
 
     @Override
-    public void setData(Map<String, Object> data) {
+    public void setData(final Map<String, Object> data) {
         this.data = data;
     }
 
diff --git a/src/main/java/de/stklcode/jvault/connector/model/response/SealResponse.java b/src/main/java/de/stklcode/jvault/connector/model/response/SealResponse.java
index 1b14a98..8a479bc 100644
--- a/src/main/java/de/stklcode/jvault/connector/model/response/SealResponse.java
+++ b/src/main/java/de/stklcode/jvault/connector/model/response/SealResponse.java
@@ -26,7 +26,7 @@ import com.fasterxml.jackson.annotation.JsonProperty;
  * @since   0.1
  */
 @JsonIgnoreProperties(ignoreUnknown = true)
-public class SealResponse implements VaultResponse {
+public final class SealResponse implements VaultResponse {
     @JsonProperty("sealed")
     private boolean sealed;
 
diff --git a/src/main/java/de/stklcode/jvault/connector/model/response/SecretListResponse.java b/src/main/java/de/stklcode/jvault/connector/model/response/SecretListResponse.java
index faf27c6..40c309b 100644
--- a/src/main/java/de/stklcode/jvault/connector/model/response/SecretListResponse.java
+++ b/src/main/java/de/stklcode/jvault/connector/model/response/SecretListResponse.java
@@ -30,11 +30,11 @@ import java.util.Map;
  * @since   0.1
  */
 @JsonIgnoreProperties(ignoreUnknown = true)
-public class SecretListResponse extends VaultDataResponse {
+public final class SecretListResponse extends VaultDataResponse {
     private List<String> keys;
 
     @JsonProperty("data")
-    public void setData(Map<String, Object> data) throws InvalidResponseException {
+    public void setData(final Map<String, Object> data) throws InvalidResponseException {
         try {
             this.keys = (List<String>)data.get("keys");
         }
diff --git a/src/main/java/de/stklcode/jvault/connector/model/response/SecretResponse.java b/src/main/java/de/stklcode/jvault/connector/model/response/SecretResponse.java
index 12204ba..c3d8ef5 100644
--- a/src/main/java/de/stklcode/jvault/connector/model/response/SecretResponse.java
+++ b/src/main/java/de/stklcode/jvault/connector/model/response/SecretResponse.java
@@ -35,7 +35,7 @@ public class SecretResponse extends VaultDataResponse {
     private Map<String, Object> data;
 
     @Override
-    public void setData(Map<String, Object> data) throws InvalidResponseException {
+    public final void setData(final Map<String, Object> data) throws InvalidResponseException {
         this.data = data;
     }
 
@@ -45,7 +45,7 @@ public class SecretResponse extends VaultDataResponse {
      * @return data map
      * @since 0.4.0
      */
-    public Map<String, Object> getData() {
+    public final Map<String, Object> getData() {
         if (data == null)
             return new HashMap<>();
         return data;
@@ -58,7 +58,7 @@ public class SecretResponse extends VaultDataResponse {
      * @return the value or NULL if absent
      * @since 0.4.0
      */
-    public Object get(String key) {
+    public final Object get(final String key) {
         if (data == null)
             return null;
         return getData().get(key);
@@ -72,7 +72,7 @@ public class SecretResponse extends VaultDataResponse {
      * @deprecated Deprecated artifact, will be removed at latest at v1.0.0
      */
     @Deprecated
-    public String getValue() {
+    public final String getValue() {
         if (get("value") == null)
             return null;
         return get("value").toString();
@@ -89,7 +89,7 @@ public class SecretResponse extends VaultDataResponse {
      * @deprecated Deprecated artifact, will be removed at latest at v1.0.0
      */
     @Deprecated
-    public <T> T getValue(Class<T> type) throws InvalidResponseException {
+    public final <T> T getValue(final Class<T> type) throws InvalidResponseException {
         return get("value", type);
     }
 
@@ -103,11 +103,11 @@ public class SecretResponse extends VaultDataResponse {
      * @throws InvalidResponseException on parsing error
      * @since 0.4.0
      */
-    public <T> T get(String key, Class<T> type) throws InvalidResponseException {
+    public final <T> T get(final String key, final Class<T> type) throws InvalidResponseException {
         try {
             return new ObjectMapper().readValue(get(key).toString(), type);
         } catch (IOException e) {
             throw new InvalidResponseException("Unable to parse response payload: " + e.getMessage());
         }
     }
-}
\ No newline at end of file
+}
diff --git a/src/main/java/de/stklcode/jvault/connector/model/response/TokenResponse.java b/src/main/java/de/stklcode/jvault/connector/model/response/TokenResponse.java
index 99d6b01..0221082 100644
--- a/src/main/java/de/stklcode/jvault/connector/model/response/TokenResponse.java
+++ b/src/main/java/de/stklcode/jvault/connector/model/response/TokenResponse.java
@@ -32,14 +32,14 @@ import java.util.Map;
  * @since   0.1
  */
 @JsonIgnoreProperties(ignoreUnknown = true)
-public class TokenResponse extends VaultDataResponse {
+public final class TokenResponse extends VaultDataResponse {
     private TokenData data;
 
     @JsonProperty("auth")
     private Boolean auth;
 
     @Override
-    public void setData(Map<String, Object> data) throws InvalidResponseException {
+    public void setData(final Map<String, Object> data) throws InvalidResponseException {
         ObjectMapper mapper = new ObjectMapper();
         try {
             this.data = mapper.readValue(mapper.writeValueAsString(data), TokenData.class);
diff --git a/src/main/java/de/stklcode/jvault/connector/model/response/VaultDataResponse.java b/src/main/java/de/stklcode/jvault/connector/model/response/VaultDataResponse.java
index 86fb2b3..2054e33 100644
--- a/src/main/java/de/stklcode/jvault/connector/model/response/VaultDataResponse.java
+++ b/src/main/java/de/stklcode/jvault/connector/model/response/VaultDataResponse.java
@@ -42,21 +42,21 @@ public abstract class VaultDataResponse implements VaultResponse {
     private List<String> warnings;
 
     @JsonProperty("data")
-    public abstract void setData(Map<String, Object> data) throws InvalidResponseException;
+    public abstract void setData(final Map<String, Object> data) throws InvalidResponseException;
 
-    public String getLeaseId() {
+    public final String getLeaseId() {
         return leaseId;
     }
 
-    public boolean isRenewable() {
+    public final boolean isRenewable() {
         return renewable;
     }
 
-    public Integer getLeaseDuration() {
+    public final Integer getLeaseDuration() {
         return leaseDuration;
     }
 
-    public List<String> getWarnings() {
+    public final List<String> getWarnings() {
         return warnings;
     }
 }
diff --git a/src/main/java/de/stklcode/jvault/connector/model/response/embedded/AuthData.java b/src/main/java/de/stklcode/jvault/connector/model/response/embedded/AuthData.java
index b4af724..d3421c6 100644
--- a/src/main/java/de/stklcode/jvault/connector/model/response/embedded/AuthData.java
+++ b/src/main/java/de/stklcode/jvault/connector/model/response/embedded/AuthData.java
@@ -29,7 +29,7 @@ import java.util.Map;
  * @since   0.1
  */
 @JsonIgnoreProperties(ignoreUnknown = true)
-public class AuthData {
+public final class AuthData {
     @JsonProperty("client_token")
     private String clientToken;
 
diff --git a/src/main/java/de/stklcode/jvault/connector/model/response/embedded/AuthMethod.java b/src/main/java/de/stklcode/jvault/connector/model/response/embedded/AuthMethod.java
index 858f588..65c6f56 100644
--- a/src/main/java/de/stklcode/jvault/connector/model/response/embedded/AuthMethod.java
+++ b/src/main/java/de/stklcode/jvault/connector/model/response/embedded/AuthMethod.java
@@ -30,7 +30,7 @@ import java.util.Map;
  * @since   0.1
  */
 @JsonIgnoreProperties(ignoreUnknown = true)
-public class AuthMethod {
+public final class AuthMethod {
     private AuthBackend type;
     private String rawType;
 
@@ -44,7 +44,7 @@ public class AuthMethod {
     private boolean local;
 
     @JsonSetter("type")
-    public void setType(String type) {
+    public void setType(final String type) {
         this.rawType = type;
         this.type = AuthBackend.forType(type);
     }
diff --git a/src/main/java/de/stklcode/jvault/connector/model/response/embedded/TokenData.java b/src/main/java/de/stklcode/jvault/connector/model/response/embedded/TokenData.java
index 5ffaffa..0f9484f 100644
--- a/src/main/java/de/stklcode/jvault/connector/model/response/embedded/TokenData.java
+++ b/src/main/java/de/stklcode/jvault/connector/model/response/embedded/TokenData.java
@@ -26,7 +26,7 @@ import com.fasterxml.jackson.annotation.JsonProperty;
  * @since   0.1
  */
 @JsonIgnoreProperties(ignoreUnknown = true)
-public class TokenData {
+public final class TokenData {
     @JsonProperty("accessor")
     private String accessor;