// before
public enum Compatibility
    {
        Compatible, Information_missing, Not_compatible;

        public Compatibility and(Compatibility other)
        {
            if(other.equals(this)) return this;
            if(other.equals(Compatible) && this.equals(Information_missing)) return Information_missing;
            if(other.equals(Information_missing) && this.equals(Compatible)) return Information_missing;
            if(other.equals(Compatible) && this.equals(Not_compatible)) return Not_compatible;
            if(other.equals(Not_compatible) && this.equals(Compatible)) return Not_compatible;
            if(other.equals(Information_missing) && this.equals(Not_compatible)) return Not_compatible;
            if(other.equals(Not_compatible) && this.equals(Information_missing)) return Not_compatible;
            return null;
        }

        public Compatibility or(Compatibility other)
        {
            if(other.equals(this)) return this;
            if(other.equals(Compatible) && this.equals(Information_missing)) return Compatible;
            if(other.equals(Information_missing) && this.equals(Compatible)) return Compatible;
            if(other.equals(Compatible) && this.equals(Not_compatible)) return Compatible;
            if(other.equals(Not_compatible) && this.equals(Compatible)) return Compatible;
            if(other.equals(Information_missing) && this.equals(Not_compatible)) return Information_missing;
            if(other.equals(Not_compatible) && this.equals(Information_missing)) return Information_missing;
            return null;
        }
    }


// after
public enum Compatibility
    {
                public Compatibility and(Compatibility other)
        {
            if(other.equals(this)) return this;
            if(other.equals(Compatible) && this.equals(Information_missing)) return Information_missing;
            if(other.equals(Information_missing) && this.equals(Compatible)) return Information_missing;
            if(other.equals(Compatible) && this.equals(Not_compatible)) return Not_compatible;
            if(other.equals(Not_compatible) && this.equals(Compatible)) return Not_compatible;
            if(other.equals(Information_missing) && this.equals(Not_compatible)) return Not_compatible;
            if(other.equals(Not_compatible) && this.equals(Information_missing)) return Not_compatible;
            return null;
        }, Information_missing, Not_compatible;

        public Compatibility or(Compatibility other)
        {
            if(other.equals(this)) return this;
            if(other.equals(Compatible) && this.equals(Information_missing)) return Compatible;
            if(other.equals(Information_missing) && this.equals(Compatible)) return Compatible;
            if(other.equals(Compatible) && this.equals(Not_compatible)) return Compatible;
            if(other.equals(Not_compatible) && this.equals(Compatible)) return Compatible;
            if(other.equals(Information_missing) && this.equals(Not_compatible)) return Information_missing;
            if(other.equals(Not_compatible) && this.equals(Information_missing)) return Information_missing;
            return null;
        }
Compatible
    }