diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/microprofile/api.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/microprofile/api.mustache
index 175467a4a98..f6a69ff6a7c 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/microprofile/api.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/microprofile/api.mustache
@@ -8,6 +8,7 @@ import java.io.InputStream;
 import java.io.OutputStream;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 import javax.ws.rs.*;
 import javax.ws.rs.core.Response;
 import javax.ws.rs.core.MediaType;
diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/microprofile/api_test.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/microprofile/api_test.mustache
index 43b5285b967..a53acad5cf3 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/microprofile/api_test.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/microprofile/api_test.mustache
@@ -17,6 +17,7 @@ import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 {{/fullJavaUtil}}
 
 
diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/native/api.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/native/api.mustache
index b57129dcdb2..6968caa19eb 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/native/api.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/native/api.mustache
@@ -27,6 +27,7 @@ import java.util.ArrayList;
 import java.util.StringJoiner;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 {{/fullJavaUtil}}
 {{#asyncNative}}
 
diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/native/api_test.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/native/api_test.mustache
index 2f5ffae22c4..ffcf05ec30f 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/native/api_test.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/native/api_test.mustache
@@ -13,6 +13,7 @@ import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 {{/fullJavaUtil}}
 
 {{#asyncNative}}
diff --git a/samples/client/petstore/java/microprofile-rest-client/src/main/java/org/openapitools/client/api/PetApi.java b/samples/client/petstore/java/microprofile-rest-client/src/main/java/org/openapitools/client/api/PetApi.java
index 1b6a89b1ba3..01f075d1cc0 100644
--- a/samples/client/petstore/java/microprofile-rest-client/src/main/java/org/openapitools/client/api/PetApi.java
+++ b/samples/client/petstore/java/microprofile-rest-client/src/main/java/org/openapitools/client/api/PetApi.java
@@ -20,6 +20,7 @@ import java.io.InputStream;
 import java.io.OutputStream;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 import javax.ws.rs.*;
 import javax.ws.rs.core.Response;
 import javax.ws.rs.core.MediaType;
diff --git a/samples/client/petstore/java/microprofile-rest-client/src/main/java/org/openapitools/client/api/StoreApi.java b/samples/client/petstore/java/microprofile-rest-client/src/main/java/org/openapitools/client/api/StoreApi.java
index f26df5e1653..4e5844e79ad 100644
--- a/samples/client/petstore/java/microprofile-rest-client/src/main/java/org/openapitools/client/api/StoreApi.java
+++ b/samples/client/petstore/java/microprofile-rest-client/src/main/java/org/openapitools/client/api/StoreApi.java
@@ -18,6 +18,7 @@ import java.io.InputStream;
 import java.io.OutputStream;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 import javax.ws.rs.*;
 import javax.ws.rs.core.Response;
 import javax.ws.rs.core.MediaType;
diff --git a/samples/client/petstore/java/microprofile-rest-client/src/main/java/org/openapitools/client/api/UserApi.java b/samples/client/petstore/java/microprofile-rest-client/src/main/java/org/openapitools/client/api/UserApi.java
index fc8d0989eeb..41c31a4d49d 100644
--- a/samples/client/petstore/java/microprofile-rest-client/src/main/java/org/openapitools/client/api/UserApi.java
+++ b/samples/client/petstore/java/microprofile-rest-client/src/main/java/org/openapitools/client/api/UserApi.java
@@ -18,6 +18,7 @@ import java.io.InputStream;
 import java.io.OutputStream;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 import javax.ws.rs.*;
 import javax.ws.rs.core.Response;
 import javax.ws.rs.core.MediaType;
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/AnotherFakeApi.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/AnotherFakeApi.java
index 59947067502..3cc913b97c9 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/AnotherFakeApi.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/AnotherFakeApi.java
@@ -35,6 +35,7 @@ import java.util.ArrayList;
 import java.util.StringJoiner;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 import java.util.concurrent.CompletableFuture;
 
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/FakeApi.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/FakeApi.java
index c84924f6aba..32678efe202 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/FakeApi.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/FakeApi.java
@@ -43,6 +43,7 @@ import java.util.ArrayList;
 import java.util.StringJoiner;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 import java.util.concurrent.CompletableFuture;
 
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java
index ea9a7d97193..a49de3ea442 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java
@@ -35,6 +35,7 @@ import java.util.ArrayList;
 import java.util.StringJoiner;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 import java.util.concurrent.CompletableFuture;
 
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/PetApi.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/PetApi.java
index e65cb647aaf..9644e389046 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/PetApi.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/PetApi.java
@@ -38,6 +38,7 @@ import java.util.ArrayList;
 import java.util.StringJoiner;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 import java.util.concurrent.CompletableFuture;
 
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/StoreApi.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/StoreApi.java
index 82bb7296d85..c7c4bae1261 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/StoreApi.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/StoreApi.java
@@ -35,6 +35,7 @@ import java.util.ArrayList;
 import java.util.StringJoiner;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 import java.util.concurrent.CompletableFuture;
 
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/UserApi.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/UserApi.java
index 3d9893a34f4..b233c2d4bcb 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/UserApi.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/api/UserApi.java
@@ -35,6 +35,7 @@ import java.util.ArrayList;
 import java.util.StringJoiner;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 import java.util.concurrent.CompletableFuture;
 
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/AnotherFakeApi.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/AnotherFakeApi.java
index e31f3cd51f9..dacaab70438 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/AnotherFakeApi.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/AnotherFakeApi.java
@@ -35,6 +35,7 @@ import java.util.ArrayList;
 import java.util.StringJoiner;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 @javax.annotation.processing.Generated(value = "org.openapitools.codegen.languages.JavaClientCodegen")
 public class AnotherFakeApi {
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/FakeApi.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/FakeApi.java
index d12c79a0c0d..c56e2d5d8d6 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/FakeApi.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/FakeApi.java
@@ -43,6 +43,7 @@ import java.util.ArrayList;
 import java.util.StringJoiner;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 @javax.annotation.processing.Generated(value = "org.openapitools.codegen.languages.JavaClientCodegen")
 public class FakeApi {
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java
index f81bfe6b042..8da78d9b634 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java
@@ -35,6 +35,7 @@ import java.util.ArrayList;
 import java.util.StringJoiner;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 @javax.annotation.processing.Generated(value = "org.openapitools.codegen.languages.JavaClientCodegen")
 public class FakeClassnameTags123Api {
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/PetApi.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/PetApi.java
index 36cdfe2419d..64a58769c0d 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/PetApi.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/PetApi.java
@@ -38,6 +38,7 @@ import java.util.ArrayList;
 import java.util.StringJoiner;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 @javax.annotation.processing.Generated(value = "org.openapitools.codegen.languages.JavaClientCodegen")
 public class PetApi {
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/StoreApi.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/StoreApi.java
index 7ff31d54a16..6c438704f08 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/StoreApi.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/StoreApi.java
@@ -35,6 +35,7 @@ import java.util.ArrayList;
 import java.util.StringJoiner;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 @javax.annotation.processing.Generated(value = "org.openapitools.codegen.languages.JavaClientCodegen")
 public class StoreApi {
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/UserApi.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/UserApi.java
index 3d657dacaea..7884a482ece 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/UserApi.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/UserApi.java
@@ -35,6 +35,7 @@ import java.util.ArrayList;
 import java.util.StringJoiner;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 @javax.annotation.processing.Generated(value = "org.openapitools.codegen.languages.JavaClientCodegen")
 public class UserApi {