diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/ApiClient.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/ApiClient.mustache
index 1f0e606d873a..1c068bcc58d3 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/ApiClient.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/ApiClient.mustache
@@ -30,6 +30,7 @@ import java.io.IOException;
 import java.io.InputStream;
 import java.io.UnsupportedEncodingException;
 import java.lang.reflect.Type;
+import java.net.URI;
 import java.net.URLConnection;
 import java.net.URLEncoder;
 import java.security.GeneralSecurityException;
@@ -122,10 +123,30 @@ public class ApiClient {
      * Constructor for ApiClient to support access token retry on 401/403 configured with client ID, secret, and additional parameters
      */
     public ApiClient(String clientId, String clientSecret, Map<String, String> parameters) {
+        this(null, clientId, clientSecret, parameters);
+    }
+
+    /*
+     * Constructor for ApiClient to support access token retry on 401/403 configured with base path, client ID, secret, and additional parameters
+     */
+    public ApiClient(String basePath, String clientId, String clientSecret, Map<String, String> parameters) {
         init();
+        if (basePath != null) {
+            this.basePath = basePath;
+        }
 
 {{#hasOAuthMethods}}
-        RetryingOAuth retryingOAuth = new RetryingOAuth("{{tokenUrl}}", clientId, OAuthFlow.{{flow}}, clientSecret, parameters);
+        String tokenUrl = "{{tokenUrl}}";
+        if (!"".equals(tokenUrl) && !URI.create(tokenUrl).isAbsolute()) {
+            URI uri = URI.create(getBasePath());
+            tokenUrl = uri.getScheme() + ":" +
+                (uri.getAuthority() != null ? "//" + uri.getAuthority() : "") +
+                tokenUrl;
+            if (!URI.create(tokenUrl).isAbsolute()) {
+                throw new IllegalArgumentException("OAuth2 token URL must be an absolute URL");
+            }
+        }
+        RetryingOAuth retryingOAuth = new RetryingOAuth(tokenUrl, clientId, OAuthFlow.{{flow}}, clientSecret, parameters);
         authentications.put(
                 "{{name}}",
                 retryingOAuth
diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/auth/RetryingOAuth.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/auth/RetryingOAuth.mustache
index 94f1d6afcf90..3ddacedb70e6 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/auth/RetryingOAuth.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/auth/RetryingOAuth.mustache
@@ -36,6 +36,13 @@ public class RetryingOAuth extends OAuth implements Interceptor {
         this(new OkHttpClient(), tokenRequestBuilder);
     }
 
+    /**
+    @param tokenUrl The token URL to be used for this OAuth2 flow.
+        Applicable to the following OAuth2 flows: "password", "clientCredentials" and "authorizationCode".
+        The value must be an absolute URL.
+    @param clientId The OAuth2 client ID for the "clientCredentials" flow.
+    @param clientSecret The OAuth2 client secret for the "clientCredentials" flow.
+    */
     public RetryingOAuth(
             String tokenUrl,
             String clientId,
diff --git a/samples/client/petstore/java/okhttp-gson-parcelableModel/src/main/java/org/openapitools/client/ApiClient.java b/samples/client/petstore/java/okhttp-gson-parcelableModel/src/main/java/org/openapitools/client/ApiClient.java
index a83ae60c0438..cde3509dbb0b 100644
--- a/samples/client/petstore/java/okhttp-gson-parcelableModel/src/main/java/org/openapitools/client/ApiClient.java
+++ b/samples/client/petstore/java/okhttp-gson-parcelableModel/src/main/java/org/openapitools/client/ApiClient.java
@@ -32,6 +32,7 @@
 import java.io.InputStream;
 import java.io.UnsupportedEncodingException;
 import java.lang.reflect.Type;
+import java.net.URI;
 import java.net.URLConnection;
 import java.net.URLEncoder;
 import java.security.GeneralSecurityException;
@@ -114,9 +115,29 @@ public ApiClient(String clientId, Map<String, String> parameters) {
      * Constructor for ApiClient to support access token retry on 401/403 configured with client ID, secret, and additional parameters
      */
     public ApiClient(String clientId, String clientSecret, Map<String, String> parameters) {
+        this(null, clientId, clientSecret, parameters);
+    }
+
+    /*
+     * Constructor for ApiClient to support access token retry on 401/403 configured with base path, client ID, secret, and additional parameters
+     */
+    public ApiClient(String basePath, String clientId, String clientSecret, Map<String, String> parameters) {
         init();
+        if (basePath != null) {
+            this.basePath = basePath;
+        }
 
-        RetryingOAuth retryingOAuth = new RetryingOAuth("", clientId, OAuthFlow.implicit, clientSecret, parameters);
+        String tokenUrl = "";
+        if (!"".equals(tokenUrl) && !URI.create(tokenUrl).isAbsolute()) {
+            URI uri = URI.create(getBasePath());
+            tokenUrl = uri.getScheme() + ":" +
+                (uri.getAuthority() != null ? "//" + uri.getAuthority() : "") +
+                tokenUrl;
+            if (!URI.create(tokenUrl).isAbsolute()) {
+                throw new IllegalArgumentException("OAuth2 token URL must be an absolute URL");
+            }
+        }
+        RetryingOAuth retryingOAuth = new RetryingOAuth(tokenUrl, clientId, OAuthFlow.implicit, clientSecret, parameters);
         authentications.put(
                 "petstore_auth",
                 retryingOAuth
diff --git a/samples/client/petstore/java/okhttp-gson-parcelableModel/src/main/java/org/openapitools/client/auth/RetryingOAuth.java b/samples/client/petstore/java/okhttp-gson-parcelableModel/src/main/java/org/openapitools/client/auth/RetryingOAuth.java
index 965351d06359..9cab81a71767 100644
--- a/samples/client/petstore/java/okhttp-gson-parcelableModel/src/main/java/org/openapitools/client/auth/RetryingOAuth.java
+++ b/samples/client/petstore/java/okhttp-gson-parcelableModel/src/main/java/org/openapitools/client/auth/RetryingOAuth.java
@@ -35,6 +35,13 @@ public RetryingOAuth(TokenRequestBuilder tokenRequestBuilder) {
         this(new OkHttpClient(), tokenRequestBuilder);
     }
 
+    /**
+    @param tokenUrl The token URL to be used for this OAuth2 flow.
+        Applicable to the following OAuth2 flows: "password", "clientCredentials" and "authorizationCode".
+        The value must be an absolute URL.
+    @param clientId The OAuth2 client ID for the "clientCredentials" flow.
+    @param clientSecret The OAuth2 client secret for the "clientCredentials" flow.
+    */
     public RetryingOAuth(
             String tokenUrl,
             String clientId,
diff --git a/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/ApiClient.java b/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/ApiClient.java
index a83ae60c0438..cde3509dbb0b 100644
--- a/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/ApiClient.java
+++ b/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/ApiClient.java
@@ -32,6 +32,7 @@
 import java.io.InputStream;
 import java.io.UnsupportedEncodingException;
 import java.lang.reflect.Type;
+import java.net.URI;
 import java.net.URLConnection;
 import java.net.URLEncoder;
 import java.security.GeneralSecurityException;
@@ -114,9 +115,29 @@ public ApiClient(String clientId, Map<String, String> parameters) {
      * Constructor for ApiClient to support access token retry on 401/403 configured with client ID, secret, and additional parameters
      */
     public ApiClient(String clientId, String clientSecret, Map<String, String> parameters) {
+        this(null, clientId, clientSecret, parameters);
+    }
+
+    /*
+     * Constructor for ApiClient to support access token retry on 401/403 configured with base path, client ID, secret, and additional parameters
+     */
+    public ApiClient(String basePath, String clientId, String clientSecret, Map<String, String> parameters) {
         init();
+        if (basePath != null) {
+            this.basePath = basePath;
+        }
 
-        RetryingOAuth retryingOAuth = new RetryingOAuth("", clientId, OAuthFlow.implicit, clientSecret, parameters);
+        String tokenUrl = "";
+        if (!"".equals(tokenUrl) && !URI.create(tokenUrl).isAbsolute()) {
+            URI uri = URI.create(getBasePath());
+            tokenUrl = uri.getScheme() + ":" +
+                (uri.getAuthority() != null ? "//" + uri.getAuthority() : "") +
+                tokenUrl;
+            if (!URI.create(tokenUrl).isAbsolute()) {
+                throw new IllegalArgumentException("OAuth2 token URL must be an absolute URL");
+            }
+        }
+        RetryingOAuth retryingOAuth = new RetryingOAuth(tokenUrl, clientId, OAuthFlow.implicit, clientSecret, parameters);
         authentications.put(
                 "petstore_auth",
                 retryingOAuth
diff --git a/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/auth/RetryingOAuth.java b/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/auth/RetryingOAuth.java
index 965351d06359..9cab81a71767 100644
--- a/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/auth/RetryingOAuth.java
+++ b/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/auth/RetryingOAuth.java
@@ -35,6 +35,13 @@ public RetryingOAuth(TokenRequestBuilder tokenRequestBuilder) {
         this(new OkHttpClient(), tokenRequestBuilder);
     }
 
+    /**
+    @param tokenUrl The token URL to be used for this OAuth2 flow.
+        Applicable to the following OAuth2 flows: "password", "clientCredentials" and "authorizationCode".
+        The value must be an absolute URL.
+    @param clientId The OAuth2 client ID for the "clientCredentials" flow.
+    @param clientSecret The OAuth2 client secret for the "clientCredentials" flow.
+    */
     public RetryingOAuth(
             String tokenUrl,
             String clientId,