Show enum values on GSP page and then bind them in the database

I have a use case in which I need to first show the value of enum on the GSP page first as a drop down list, have the user select one of those values and then finally bind the data to the domain.

So my code on GSP looks like my enum is MyEnum

<g:select from="${MyEnum.getAllEnumList()}" optionValue="name" name="duration"/>

my enum is

public enum MyEnum {

    MIN15('15 Minutes'),
    MIN30('30 Minutes'),
    HOUR1('1 Hour'),
    HOUR2('2 Hours'),
    HOUR5('5 Hours'),
    HOUR8('8 Hours'),
    HALFDAY('half day'),
    FULLDAY('full day')

    private final String name
    private final String displayName

    public static final List<MyEnum> getAllEnumList() {
        [MIN15,MIN30,HOUR1,HOUR2,HOUR5,HOUR8,HALFDAY,FULLDAY]
    }

    public String toString() {
        return displayName
    }

    MyEnum(String name,String displayName) {
        this.name = name
        this.displayName = displayName;
    }

}

when I hit the page its showing an error like:

Error processing GroovyPageView: Error executing tag <g:form>: Error evaluating expression [MyEnum.getAllEnumList()] on line [37]: java.lang.NoClassDefFoundError: Could not initialize class ENUM.MyEnum at D:/myspace/projects/IcepushpluginSampleApp/grails-app/views/util/test.gsp:46

Any ideas ????