diff --git a/modules/swagger-core/src/main/java/io/swagger/v3/core/util/AnnotationsUtils.java b/modules/swagger-core/src/main/java/io/swagger/v3/core/util/AnnotationsUtils.java
index 372bbcd5f5..f90f5d569f 100644
--- a/modules/swagger-core/src/main/java/io/swagger/v3/core/util/AnnotationsUtils.java
+++ b/modules/swagger-core/src/main/java/io/swagger/v3/core/util/AnnotationsUtils.java
@@ -1079,7 +1079,10 @@ public static Schema resolveSchemaFromType(Class<?> schemaImplementation,
                 existingSchemaObject = reResolvedSchema.get();
             }
         }
-        if (StringUtils.isBlank(existingSchemaObject.get$ref()) && StringUtils.isBlank(existingSchemaObject.getType())) {
+        boolean doesSchemaHaveNullOrEmptyTypes = existingSchemaObject.getTypes() == null || existingSchemaObject.getTypes().isEmpty();
+        if (StringUtils.isBlank(existingSchemaObject.get$ref())
+                && StringUtils.isBlank(existingSchemaObject.getType())
+                && doesSchemaHaveNullOrEmptyTypes) {
             // default to string
             existingSchemaObject.setType("string");
         }
diff --git a/modules/swagger-jaxrs2/src/test/java/io/swagger/v3/jaxrs2/APIResponsesResourceTest.java b/modules/swagger-jaxrs2/src/test/java/io/swagger/v3/jaxrs2/APIResponsesResourceTest.java
new file mode 100644
index 0000000000..90e48b8833
--- /dev/null
+++ b/modules/swagger-jaxrs2/src/test/java/io/swagger/v3/jaxrs2/APIResponsesResourceTest.java
@@ -0,0 +1,35 @@
+package io.swagger.v3.jaxrs2;
+
+import io.swagger.v3.jaxrs2.matchers.SerializationMatchers;
+import io.swagger.v3.jaxrs2.resources.APIResponsesResource;
+import io.swagger.v3.oas.integration.SwaggerConfiguration;
+import io.swagger.v3.oas.models.OpenAPI;
+import io.swagger.v3.oas.models.media.Schema;
+import org.testng.annotations.Test;
+
+import java.util.Collections;
+
+import static org.testng.Assert.assertEquals;
+import static org.testng.Assert.assertNull;
+
+public class APIResponsesResourceTest {
+
+    @Test
+    public void testBooleanResponseSchema31() {
+        OpenAPI openAPI = new Reader(new SwaggerConfiguration().openAPI31(true))
+                .read(APIResponsesResource.class);
+
+        Schema responseSchema = openAPI.getPaths()
+                .get("/mypath")
+                .getPost()
+                .getResponses()
+                .get("200")
+                .getContent()
+                .get("*/*")
+                .getSchema();
+
+        assertNull(responseSchema.getType());
+        assertEquals(responseSchema.getTypes(), Collections.singleton("boolean"));
+        SerializationMatchers.assertEqualsToJson31(responseSchema, "{\"type\":\"boolean\"}");
+    }
+}
diff --git a/modules/swagger-jaxrs2/src/test/java/io/swagger/v3/jaxrs2/resources/APIResponsesResource.java b/modules/swagger-jaxrs2/src/test/java/io/swagger/v3/jaxrs2/resources/APIResponsesResource.java
new file mode 100644
index 0000000000..9be097e5a0
--- /dev/null
+++ b/modules/swagger-jaxrs2/src/test/java/io/swagger/v3/jaxrs2/resources/APIResponsesResource.java
@@ -0,0 +1,23 @@
+package io.swagger.v3.jaxrs2.resources;
+
+import io.swagger.v3.oas.annotations.media.Content;
+import io.swagger.v3.oas.annotations.media.Schema;
+import io.swagger.v3.oas.annotations.responses.ApiResponse;
+import io.swagger.v3.oas.annotations.responses.ApiResponses;
+
+import javax.ws.rs.POST;
+import javax.ws.rs.Path;
+
+@Path("mypath")
+public class APIResponsesResource {
+
+    @POST
+    @ApiResponses({
+            @ApiResponse(
+                    responseCode = "200",
+                    content = @Content(schema = @Schema(implementation = Boolean.class))
+            )
+    })
+    public void myMethod() {
+    }
+}