public InnerCNode getTree() throws CodegenRuntimeException {
        try {
            if (root == null) parse();
        } catch (DefParserException | IOException e) {
            throw new CodegenRuntimeException("Error parsing or reading config definition." + e.getMessage(), e);
        }
        return root;
    }
Parses the .def file upon the initial call. Subsequent calls returns the result from the initial call.

@return  A tree of CNodes representing this instance's .def file.
@throws CodegenRuntimeException upon errors.
configgen/src/main/java/com/yahoo/config/codegen/DefParser.java