[JAVA] Incorrect enum generation for integer values

Description

Java compilation is failed for a model which is generated with enum schema for integer values.

Swagger-codegen version

3.0.30

Swagger declaration file content or url

 Status:
        type: integer
        enum: [0, 1, 2]
        description: > 
          Statuses :
          * 0 Unknown
          * 1 New
          * 2 Finished

Command line used for generation

java -Dmodels -jar swagger-codegen-cli-3.0.30.jar generate -i model.yaml -l java -DmodelPackage=some.custom.package

Steps to reproduce

1. Create yaml specification with enum based on integer values
2. Generate java models with command line explained above
   Expected result:
   Generator produces compilable java entity
   Actual result:
   Generated java entity is not compilable

Java code generated by swagger-codegen

 public static class Adapter extends TypeAdapter<Status> {
    @Override
    public void write(final JsonWriter jsonWriter, final Status enumeration) throws IOException {
      jsonWriter.value(String.valueOf(enumeration.getValue()));
    }

    @Override
    public Status read(final JsonReader jsonReader) throws IOException {
      Object value = jsonReader.nextInt();
      return Status.fromValue(()(value));
    }
  }

Reproduce the issue with the supplied model.yaml and swagger-codegen-cli-3.0.30 command, then inspect the generated Java enum's Adapter and the generator templates that produce it. Confirm the generated model compiles for integer enum values, while preserving valid output for other enum types.