Fix OpenAPITools#5381

added x-is-one-of-interface extension for oneOf interface in mustache
template

Author: alexsuperdev

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/SpringCodegen.java

@@ -21,9 +21,6 @@
 import io.swagger.v3.oas.models.OpenAPI;
 import io.swagger.v3.oas.models.Operation;
 import io.swagger.v3.oas.models.PathItem;
-import io.swagger.v3.oas.models.media.ComposedSchema;
-import io.swagger.v3.oas.models.media.Schema;
-import java.util.Map.Entry;
 import org.apache.commons.lang3.tuple.Pair;
 import org.openapitools.codegen.*;
 import org.openapitools.codegen.languages.features.BeanValidationFeatures;

modules/openapi-generator/src/main/resources/JavaSpring/oneof_interface.mustache

@@ -3,4 +3,4 @@ public interface {{classname}} {{#vendorExtensions.x-implements}}{{#-first}}exte
     {{#discriminator}}
     public {{propertyType}} {{propertyGetter}}();
     {{/discriminator}}
-}
+}