In order to avoid the following pattern which is very very present :

private SomeAttribute _lazyGetSomeAttribute()
{
    if (_someAttribute == null)
    {
        _someAttribute = _loadSomeAttributeFromWhatever();
    }
    return _someAttribute;
}

which is not thread-safe (most of the time the keyword synchronized is forgotten), error-prone, is always the same (reinventing the wheel) and stil expose a private attribute _someAttribute  which can be accidentally used elsewhere and lead to a NPE.

I propose to have a class to wrap that behavior, on a similar API than in ThreadLocal, with at least those methods:

public static <T> CachedValue<T> withInitial(Supplier<T> supplier)
public T get()

I propose to have an implementation based on com.google.common.cache.LoadingCache

It has the major benefit of being thread-safe and so on, it can be more trusted than any of our own implementation

Plus it would enable some other interesting features for future improvements:

• expiry duration: the value is removed from the cache and recomputed (or not) every X seconds/minutes/hour/...
• ...

Note that I'm surprised it does not exist elsewhere. I've searched in Guava, ApacheCommons but did not find anything Maybe I did not searched the correct keywords.