In 1.5.1-M2, enum parameters in BeanParam as PathParam or QueryParam are not showing the drop down list on the swagger ui. Looking at the swagger.json, I don't see the enum values listed which seems to be issue on core side.
As a workaround, I've been using the @ApiParam with allowableValues.
Sample: field in BeanParam object:
@ApiParam(required = true, value = "type of summary report",
allowableValues = "summary,summary-jp,summary-uk",
defaultValue = "summary")
@PathParam("report_type")
@DefaultValue("summary")
@JsonProperty("report_type")
private ReportType reportType = ReportType.REP_AOP_CORE_METRICS;