diff --git a/bin/java-petstore-feign-10x.json b/bin/java-petstore-feign-10x.json
index d8f09eb65a..95949f4a93 100644
--- a/bin/java-petstore-feign-10x.json
+++ b/bin/java-petstore-feign-10x.json
@@ -1,5 +1,4 @@
 {
     "library": "feign",
-    "artifactId": "petstore-feign-10x",
-    "feignVersion": "10.x"
+    "artifactId": "petstore-feign-10x"
 }
diff --git a/docs/generators/java.md b/docs/generators/java.md
index 2c4c4691a0..2e3c153c08 100644
--- a/docs/generators/java.md
+++ b/docs/generators/java.md
@@ -22,13 +22,13 @@ sidebar_label: java
 |developerOrganizationUrl|developer organization URL in generated pom.xml| |http://openapitools.org|
 |disableHtmlEscaping|Disable HTML escaping of JSON strings when using gson (needed to avoid problems with byte[] fields)| |false|
 |ensureUniqueParams|Whether to ensure parameter names are unique in an operation (rename parameters that are not).| |true|
-|feignVersion|Version of OpenFeign: '10.x', '9.x' (default)| |false|
+|feignVersion|Version of OpenFeign: '10.x' (default), '9.x' (deprecated)| |false|
 |fullJavaUtil|whether to use fully qualified name for classes under java.util. This option only works for Java API client| |false|
 |groupId|groupId in generated pom.xml| |org.openapitools|
 |hideGenerationTimestamp|Hides the generation timestamp when files are generated.| |false|
 |invokerPackage|root package for generated code| |org.openapitools.client|
 |java8|Option. Use Java8 classes instead of third party equivalents|<dl><dt>**true**</dt><dd>Use Java 8 classes such as Base64</dd><dt>**false**</dt><dd>Various third party libraries as needed</dd></dl>|false|
-|library|library template (sub-template) to use|<dl><dt>**jersey1**</dt><dd>HTTP client: Jersey client 1.19.x. JSON processing: Jackson 2.9.x. Enable Java6 support using '-DsupportJava6=true'. Enable gzip request encoding using '-DuseGzipFeature=true'. IMPORTANT NOTE: jersey 1.x is no longer actively maintained so please upgrade to 'jersey2' or other HTTP libaries instead.</dd><dt>**jersey2**</dt><dd>HTTP client: Jersey client 2.25.1. JSON processing: Jackson 2.9.x</dd><dt>**feign**</dt><dd>HTTP client: OpenFeign 9.x or 10.x. JSON processing: Jackson 2.9.x. To enable OpenFeign 10.x, set the 'feignVersion' option to '10.x'</dd><dt>**okhttp-gson**</dt><dd>[DEFAULT] HTTP client: OkHttp 3.x. JSON processing: Gson 2.8.x. Enable Parcelable models on Android using '-DparcelableModel=true'. Enable gzip request encoding using '-DuseGzipFeature=true'.</dd><dt>**retrofit**</dt><dd>HTTP client: OkHttp 2.x. JSON processing: Gson 2.x (Retrofit 1.9.0). IMPORTANT NOTE: retrofit1.x is no longer actively maintained so please upgrade to 'retrofit2' instead.</dd><dt>**retrofit2**</dt><dd>HTTP client: OkHttp 3.x. JSON processing: Gson 2.x (Retrofit 2.3.0). Enable the RxJava adapter using '-DuseRxJava[2]=true'. (RxJava 1.x or 2.x)</dd><dt>**resttemplate**</dt><dd>HTTP client: Spring RestTemplate 4.x. JSON processing: Jackson 2.9.x</dd><dt>**webclient**</dt><dd>HTTP client: Spring WebClient 5.x. JSON processing: Jackson 2.9.x</dd><dt>**resteasy**</dt><dd>HTTP client: Resteasy client 3.x. JSON processing: Jackson 2.9.x</dd><dt>**vertx**</dt><dd>HTTP client: VertX client 3.x. JSON processing: Jackson 2.9.x</dd><dt>**google-api-client**</dt><dd>HTTP client: Google API client 1.x. JSON processing: Jackson 2.9.x</dd><dt>**rest-assured**</dt><dd>HTTP client: rest-assured : 4.x. JSON processing: Gson 2.x or Jackson 2.9.x. Only for Java8</dd><dt>**native**</dt><dd>HTTP client: Java native HttpClient. JSON processing: Jackson 2.9.x. Only for Java11+</dd><dt>**microprofile**</dt><dd>HTTP client: Microprofile client X.x. JSON processing: Jackson 2.9.x</dd></dl>|okhttp-gson|
+|library|library template (sub-template) to use|<dl><dt>**jersey1**</dt><dd>HTTP client: Jersey client 1.19.x. JSON processing: Jackson 2.9.x. Enable Java6 support using '-DsupportJava6=true'. Enable gzip request encoding using '-DuseGzipFeature=true'. IMPORTANT NOTE: jersey 1.x is no longer actively maintained so please upgrade to 'jersey2' or other HTTP libaries instead.</dd><dt>**jersey2**</dt><dd>HTTP client: Jersey client 2.25.1. JSON processing: Jackson 2.9.x</dd><dt>**feign**</dt><dd>HTTP client: OpenFeign 9.x (deprecated) or 10.x (default). JSON processing: Jackson 2.9.x.</dd><dt>**okhttp-gson**</dt><dd>[DEFAULT] HTTP client: OkHttp 3.x. JSON processing: Gson 2.8.x. Enable Parcelable models on Android using '-DparcelableModel=true'. Enable gzip request encoding using '-DuseGzipFeature=true'.</dd><dt>**retrofit**</dt><dd>HTTP client: OkHttp 2.x. JSON processing: Gson 2.x (Retrofit 1.9.0). IMPORTANT NOTE: retrofit1.x is no longer actively maintained so please upgrade to 'retrofit2' instead.</dd><dt>**retrofit2**</dt><dd>HTTP client: OkHttp 3.x. JSON processing: Gson 2.x (Retrofit 2.3.0). Enable the RxJava adapter using '-DuseRxJava[2]=true'. (RxJava 1.x or 2.x)</dd><dt>**resttemplate**</dt><dd>HTTP client: Spring RestTemplate 4.x. JSON processing: Jackson 2.9.x</dd><dt>**webclient**</dt><dd>HTTP client: Spring WebClient 5.x. JSON processing: Jackson 2.9.x</dd><dt>**resteasy**</dt><dd>HTTP client: Resteasy client 3.x. JSON processing: Jackson 2.9.x</dd><dt>**vertx**</dt><dd>HTTP client: VertX client 3.x. JSON processing: Jackson 2.9.x</dd><dt>**google-api-client**</dt><dd>HTTP client: Google API client 1.x. JSON processing: Jackson 2.9.x</dd><dt>**rest-assured**</dt><dd>HTTP client: rest-assured : 4.x. JSON processing: Gson 2.x or Jackson 2.9.x. Only for Java8</dd><dt>**native**</dt><dd>HTTP client: Java native HttpClient. JSON processing: Jackson 2.9.x. Only for Java11+</dd><dt>**microprofile**</dt><dd>HTTP client: Microprofile client X.x. JSON processing: Jackson 2.9.x</dd></dl>|okhttp-gson|
 |licenseName|The name of the license| |Unlicense|
 |licenseUrl|The URL of the license| |http://unlicense.org|
 |modelPackage|package for generated models| |org.openapitools.client.model|
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JavaClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JavaClientCodegen.java
index 6aa926c085..fe79a9641f 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JavaClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JavaClientCodegen.java
@@ -17,6 +17,8 @@
 
 package org.openapitools.codegen.languages;
 
+import io.swagger.v3.oas.models.Operation;
+import io.swagger.v3.oas.models.media.Schema;
 import org.apache.commons.lang3.BooleanUtils;
 import org.apache.commons.lang3.StringUtils;
 import org.openapitools.codegen.*;
@@ -29,9 +31,6 @@ import org.openapitools.codegen.utils.ProcessUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import io.swagger.v3.oas.models.Operation;
-import io.swagger.v3.oas.models.media.Schema;
-
 import java.io.File;
 import java.util.*;
 import java.util.regex.Pattern;
@@ -93,7 +92,7 @@ public class JavaClientCodegen extends AbstractJavaCodegen
     protected boolean doNotUseRx = true;
     protected boolean usePlayWS = false;
     protected String playVersion = PLAY_25;
-    protected String feignVersion = FEIGN_9;
+    protected String feignVersion = FEIGN_10;
     protected boolean parcelableModel = false;
     protected boolean useBeanValidation = false;
     protected boolean performBeanValidation = false;
@@ -136,13 +135,13 @@ public class JavaClientCodegen extends AbstractJavaCodegen
         cliOptions.add(CliOption.newBoolean(PERFORM_BEANVALIDATION, "Perform BeanValidation"));
         cliOptions.add(CliOption.newBoolean(USE_GZIP_FEATURE, "Send gzip-encoded requests"));
         cliOptions.add(CliOption.newBoolean(USE_RUNTIME_EXCEPTION, "Use RuntimeException instead of Exception"));
-        cliOptions.add(CliOption.newBoolean(FEIGN_VERSION, "Version of OpenFeign: '10.x', '9.x' (default)"));
+        cliOptions.add(CliOption.newBoolean(FEIGN_VERSION, "Version of OpenFeign: '10.x' (default), '9.x' (deprecated)"));
         cliOptions.add(CliOption.newBoolean(USE_REFLECTION_EQUALS_HASHCODE, "Use org.apache.commons.lang3.builder for equals and hashCode in the models. WARNING: This will fail under a security manager, unless the appropriate permissions are set up correctly and also there's potential performance impact."));
         cliOptions.add(CliOption.newBoolean(CASE_INSENSITIVE_RESPONSE_HEADERS, "Make API response's headers case-insensitive. Available on " + OKHTTP_GSON + ", " + JERSEY2 + " libraries"));
 
         supportedLibraries.put(JERSEY1, "HTTP client: Jersey client 1.19.x. JSON processing: Jackson 2.9.x. Enable Java6 support using '-DsupportJava6=true'. Enable gzip request encoding using '-DuseGzipFeature=true'. IMPORTANT NOTE: jersey 1.x is no longer actively maintained so please upgrade to 'jersey2' or other HTTP libaries instead.");
         supportedLibraries.put(JERSEY2, "HTTP client: Jersey client 2.25.1. JSON processing: Jackson 2.9.x");
-        supportedLibraries.put(FEIGN, "HTTP client: OpenFeign 9.x or 10.x. JSON processing: Jackson 2.9.x. To enable OpenFeign 10.x, set the 'feignVersion' option to '10.x'");
+        supportedLibraries.put(FEIGN, "HTTP client: OpenFeign 9.x (deprecated) or 10.x (default). JSON processing: Jackson 2.9.x.");
         supportedLibraries.put(OKHTTP_GSON, "[DEFAULT] HTTP client: OkHttp 3.x. JSON processing: Gson 2.8.x. Enable Parcelable models on Android using '-DparcelableModel=true'. Enable gzip request encoding using '-DuseGzipFeature=true'.");
         supportedLibraries.put(RETROFIT_1, "HTTP client: OkHttp 2.x. JSON processing: Gson 2.x (Retrofit 1.9.0). IMPORTANT NOTE: retrofit1.x is no longer actively maintained so please upgrade to 'retrofit2' instead.");
         supportedLibraries.put(RETROFIT_2, "HTTP client: OkHttp 3.x. JSON processing: Gson 2.x (Retrofit 2.3.0). Enable the RxJava adapter using '-DuseRxJava[2]=true'. (RxJava 1.x or 2.x)");
@@ -197,8 +196,7 @@ public class JavaClientCodegen extends AbstractJavaCodegen
     public void processOpts() {
         if ((WEBCLIENT.equals(getLibrary()) && "threetenbp".equals(dateLibrary)) || NATIVE.equals(getLibrary())) {
             dateLibrary = "java8";
-        }
-        else if (MICROPROFILE.equals(getLibrary())) {
+        } else if (MICROPROFILE.equals(getLibrary())) {
             dateLibrary = "legacy";
         }
 
@@ -235,10 +233,14 @@ public class JavaClientCodegen extends AbstractJavaCodegen
             if ("10.x".equals(feignVersion)) {
                 additionalProperties.put("useFeign10", true);
             } else if ("9.x".equals(feignVersion)) {
-                // do nothing as 9.x is the default
+                additionalProperties.put("useFeign10", false);
+                once(LOGGER).warn("Feign 9.x support has been deprecated. Please use 10.x (default) instead.");
             } else {
-                throw new RuntimeException("Ivalid feignOoption '{}'. Must be '10.x' or '9.x'.");
+                throw new RuntimeException("Ivalid feignOoption '{}'. Must be '10.x' or '9.x' (deprecated).");
             }
+        } else {
+            // default to feign 10.x
+            additionalProperties.put("useFeign10", true);
         }
         additionalProperties.put(FEIGN_VERSION, feignVersion);
 
@@ -390,11 +392,11 @@ public class JavaClientCodegen extends AbstractJavaCodegen
             forceSerializationLibrary(SERIALIZATION_LIBRARY_JACKSON);
 
         } else if (REST_ASSURED.equals(getLibrary())) {
-            if(getSerializationLibrary() == null) {
-                LOGGER.info("No serializationLibrary configured, using '"+SERIALIZATION_LIBRARY_GSON+"' as fallback");
+            if (getSerializationLibrary() == null) {
+                LOGGER.info("No serializationLibrary configured, using '" + SERIALIZATION_LIBRARY_GSON + "' as fallback");
                 setSerializationLibrary(SERIALIZATION_LIBRARY_GSON);
             }
-            if(SERIALIZATION_LIBRARY_JACKSON.equals(getSerializationLibrary())) {
+            if (SERIALIZATION_LIBRARY_JACKSON.equals(getSerializationLibrary())) {
                 supportingFiles.add(new SupportingFile("JacksonObjectMapper.mustache", invokerFolder, "JacksonObjectMapper.java"));
             } else if (SERIALIZATION_LIBRARY_GSON.equals(getSerializationLibrary())) {
                 supportingFiles.add(new SupportingFile("JSON.mustache", invokerFolder, "JSON.java"));
@@ -468,11 +470,11 @@ public class JavaClientCodegen extends AbstractJavaCodegen
             forceSerializationLibrary(SERIALIZATION_LIBRARY_JACKSON);
         }
 
-        if(getSerializationLibrary() == null) {
-            LOGGER.info("No serializationLibrary configured, using '"+SERIALIZATION_LIBRARY_GSON+"' as fallback");
+        if (getSerializationLibrary() == null) {
+            LOGGER.info("No serializationLibrary configured, using '" + SERIALIZATION_LIBRARY_GSON + "' as fallback");
             setSerializationLibrary(SERIALIZATION_LIBRARY_GSON);
         }
-        if(SERIALIZATION_LIBRARY_JACKSON.equals(getSerializationLibrary())) {
+        if (SERIALIZATION_LIBRARY_JACKSON.equals(getSerializationLibrary())) {
             additionalProperties.put(SERIALIZATION_LIBRARY_JACKSON, "true");
             additionalProperties.remove(SERIALIZATION_LIBRARY_GSON);
             if (!NATIVE.equals(getLibrary())) {
@@ -681,6 +683,7 @@ public class JavaClientCodegen extends AbstractJavaCodegen
             model.imports.remove("ToStringSerializer");
         }
     }
+
     @Override
     public CodegenModel fromModel(String name, Schema model) {
         CodegenModel codegenModel = super.fromModel(name, model);
@@ -821,6 +824,7 @@ public class JavaClientCodegen extends AbstractJavaCodegen
 
     /**
      * Serialization library.
+     *
      * @return 'gson' or 'jackson'
      */
     public String getSerializationLibrary() {
@@ -828,9 +832,9 @@ public class JavaClientCodegen extends AbstractJavaCodegen
     }
 
     public void setSerializationLibrary(String serializationLibrary) {
-        if(SERIALIZATION_LIBRARY_JACKSON.equalsIgnoreCase(serializationLibrary)) {
+        if (SERIALIZATION_LIBRARY_JACKSON.equalsIgnoreCase(serializationLibrary)) {
             this.serializationLibrary = SERIALIZATION_LIBRARY_JACKSON;
-        } else if(SERIALIZATION_LIBRARY_GSON.equalsIgnoreCase(serializationLibrary)) {
+        } else if (SERIALIZATION_LIBRARY_GSON.equalsIgnoreCase(serializationLibrary)) {
             this.serializationLibrary = SERIALIZATION_LIBRARY_GSON;
         } else {
             throw new IllegalArgumentException("Unexpected serializationLibrary value: " + serializationLibrary);
@@ -838,7 +842,7 @@ public class JavaClientCodegen extends AbstractJavaCodegen
     }
 
     public void forceSerializationLibrary(String serializationLibrary) {
-        if((this.serializationLibrary != null) && !this.serializationLibrary.equalsIgnoreCase(serializationLibrary)) {
+        if ((this.serializationLibrary != null) && !this.serializationLibrary.equalsIgnoreCase(serializationLibrary)) {
             LOGGER.warn("The configured serializationLibrary '" + this.serializationLibrary + "', is not supported by the library: '" + getLibrary() + "', switching back to: " + serializationLibrary);
         }
         setSerializationLibrary(serializationLibrary);
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 1d3511364c..1f0e606d87 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
@@ -151,8 +151,8 @@ public class ApiClient {
             builder.addInterceptor(interceptor);
         }
         {{#useGzipFeature}}
-            // Enable gzip request compression
-            builder.addInterceptor(new GzipRequestInterceptor());
+        // Enable gzip request compression
+        builder.addInterceptor(new GzipRequestInterceptor());
         {{/useGzipFeature}}
 
         httpClient = builder.build();