We want to schedule text SMS message from our Java application.
We have checked the documentation on scheduling the RingCentral API which we haven't found any.
Does RingCentral has any feature of sending messages in schedule?
RingCentral by itself doesn't have any feature of scheduling it's API.
Since as you are using Java as a programming language, you can use Java scheduler to scheduler the API trigger at a particular interval of time.
Java schedular ref here.