components:
  schemas:
    Echo:
      type: object
      properties:
        echoedMsgType:
          type: string
    Message:
      type: object
      required:
        - msgType
      properties:
        msgType:
          type: number    <---
          enum:
            - 1          <---

@JsonIgnoreProperties(ignoreUnknown = true)
public class Message  {


    public enum MsgTypeEnum {
        NUMBER_1(BigDecimal.valueOf(new BigDecimal("1")));    // THIS IS NOT COMPILING

        // caching enum access
        private static final java.util.EnumSet<MsgTypeEnum> values = java.util.EnumSet.allOf(MsgTypeEnum.class);

        BigDecimal value;