You can do 
ThirdPartyEnum.valueOf("ABC");
Just to add, and relating to the lookupEnumForString() method you mentioned, if you wanted to search an enumerated value by one of its attributes, you could use values(). Note that values() is public, and you could also use it in case of a third party enum over which you don't have control.
public enum MyEnum {
    VAL1("1"), VAL2("2");
    String attr;
    private MyEnum(String attr){
        this.attr = attr;
    }
    public String getAttr() { return attr; }
    public static MyEnum getByAttr(String searchAttr) {
        for(MyEnum t : values()){
            if(searchAttr.equals(t.getAttr())){
                return t;
            }
        }
    }
}