I am new to programming and am a university student. While Computer Science is not my area of study, I am majoring in a subject that branches off computer science and health informatics, which deals with databases. I am currently in a programming fundamentals course at my university. My instructor mentioned that he develops in Java, but I have heard many good things about Python and JavaScript before taking his course; while we are only doing the fundamentals, I believe he is teaching us some in Java.
Since I am new to this, I'm not sure what I like more. I have also been self-teaching before this course but have not gotten deep into a particular language's fundamentals. I want to decide on a language and stick to it before I move to a new one after the first language is learned, but it is difficult deciding which language to start with. I want to develop medical software and medical mobile apps.
The only way to solve this problem while avoiding opinions and tastes is to objectively look at what you are trying to build.
Thus the most efficient part of your question is your last sentence: you want to build medical software and medical mobile apps.
In that case, the answer is definitely Java, as is for all "real" software projects.
Python is good for data science, in other words for statistics. Its other competitive advantage is that it is easy to learn for beginners, but that would be a bad reason to use it for a "real" software project.
JavaScript is a mess you don't want to get into. The major reason why it's popular is that many people learn it first, because its very basic features are easy to learn, although they don't get you far, and because it used to have exclusivity on the web. But in reality it will make your life a lot harder after a few weeks, without any benefit. I know I'll get criticisms for that, but I stand fully by this position.
There's a reason many universities start with Java- it has strict rules and lays out code in a straightforward (if excessively-boiler-plate-heavy) way. For a beginner, Java is an excellent way to learn the fundamentals of programming before taking off the training wheels and continuing in more flexible, less-syntactically-rigorous direction like Python or JavaScript.
Sticking to a language before moving on is a common goal. However, in reality you are going to transition as you find languages that better suit you or your organization's requirements. Start with Java, not because it is optimal for your end goals, but because it will teach you what you like and dislike about programming and because your instructor is more familiar with it. That will give you a valuable perspective and allow you to make a more informed decision later.
There are many ways to solve problems in different languages, but the "best" language pragmatically is the one that you feel most comfortable using. In that respect, programming is like woodworking- you want to let the tool do the work. If there is another language that is "better" objectively but more difficult or confusing to you, you will counteract the anticipated benefits by having to struggle to write code.
