presto-main/src/main/java/io/prestosql/operator/aggregation/state/StateCompiler.java/StateCompiler/getGetter
class StateCompiler:    private static Method getGetter(Class<?> clazz, StateField field)
    {
        try {
            return clazz.getMethod(field.getGetterName());
        }
        catch (NoSuchMethodException e) {
            throw new RuntimeException(e);
        }
    }