FuelSDK-Java (http://salesforce-marketingcloud.github.io/FuelSDK-Java/), being actively maintained? I noticed the primary contributor (Ian Murdock) unfortunately passed away, so I’m a little concerned about the codes ongoing maintenance given that he appeared to be the main contributor. The way this API is described is a wrapper around both the REST and SOAP API’s, so that’s what I have been primarily trying to use.
Looking at the Issues log on GitHub, there are 16 open issues, and 8 of them are assigned to Ian.
Given that they are listed off of the official Salesforce documentation pages (https://code.exacttarget.com/apis-sdks/fuel-sdks/), I hope that these are being maintained.