It all depends on the country, region, level of knowledge and most importantly the developer's experience. If interested, read this article https://diceus.com/java-developer-salary/ There are many good tips, and talk about the level of salaries of developers in the international arena.My advice. just choose whatever language you like. then have a great momentum on start. keep on improve. try to learn about others language/technology along the way.
Java is one of the most popular programming languages and one of my personal favorites. Here you would find a major research with salaries of different developers over the world. Obviously, it really depends on the location and skills sets.
These are the average salaries taken from PayScale:
Java developers salaries directly depend on your experience, the city/state you live in etc. For example, the average Java developer salary in the USA is $102K per year, however living in the UK you will be paying $59,268.