Java generator issue proof - arraylist instead of Set

spec.json

{
  "openapi" : "3.0.1",
  "info" : {
    "title" : "Issue sample",
    "version" : "1",
    "contact": {},
    "description": "Issue example"
  },
  "servers" : [],
  "paths" : {
    "/example" : {
      "get" : {
        "operationId" : "getSettings",
        "responses" : {
          "default" : {
            "description" : "default response",
            "content" : {
              "application/json" : {
                "schema" : {
                  "$ref" : "#/components/schemas/exampleDTO"
                }
              }
            }
          }
        }
      }
    }
  },
  "components" : {
    "schemas" : {
      "exampleDTO" : {
        "type" : "object",
        "properties" : {
          "enumSet" : {
            "uniqueItems" : true,
            "type" : "array",
            "items" : {
              "type" : "string",
              "enum" : [ "ENTRYONE", "ENTRYTWO" ]
            }
          }
        }
      }
    }
  }
}