As a hardcore Java/JavaScript guy myself, who had plans to develop my own wrapper until I found yours, I find this comment a little disheartening and makes me slightly weary because if you go under the 'proverbial bus' then there is no continuity or expertise immediately up to speed to provide continuity. And the last thing an open source project needs is then an ongoing power struggle in the event that you die a gruesome death or you simply get bored of the project and let it fester :-) If you are an old timer like me then probably you will provide stewardship of your creation for years to come as not much changes career wise once you are settled. But if you are in your 20s and single then life will offer you countless choices which can drag you away from this API.

The other point is that you won't be in a position to react fast enough to and sweeping changes to the underlying STEEM API. I have been burned by this before so I want to share the experience.
I was a Facebook app developer right at the point they opened up to developers in 2007 and at that time Facebook made huge breaking changes every few months, and many API wrappers fell by the way side because they could no keep up and react to the changes. I know because the C#.NET API I was using at the time was one of the casualties and over night all my apps broke and I had to replace so much code. I don't think I ever really recovered from it as I had a plethora of apps back then and a large user base and it was an absolute nightmare to deal with.

Please, please, I'm urging you to get others on board while there is loads of dev to do, and keep them there as co-devs going forward. Better having too many people with expertise rather than too few - and you can still lead the way. It doesn't detract in any way from your achievement by having more people on board and in fact it makes it a greater achievement and makes your project more likely to stand the test of time.

Also with more people there will probably numerous ideas that you haven't thought of, because nobody thinks of everything, and more ideas means more development to do......

I don't mean this to sound like a critical post - it's really not. Congrats for what you have put together and as a full stack Java developer I am very happy to have it - I started to look at it just last night and I expect it will do what I want to do. And indeed as I get stuck in I am sure I will volunteer myself to contribute....