There are better languages than other for certain purposes
. Some languages were created either as an experiment (probably some professor or grad student's project) (Brain F*** being the most notable), others were created by companies to work with a certain hardware/optimized for the task at hand (SQL, most scripting languages fall into this category), and some languages were designed to be catch-all (most modern commonly used languages).
Assembly STILL is useful! You may or may not know this, but assembly is used to program many micro controllers. These are used for alarm clocks, some circuitry in your cars, and many other uses. It is also used for high-powered computing, or when a certain piece of code needs to be as efficient as possible. This is why some programming languages (C/C++) still support and people still use the assembly
There is still yet another 3rd category of why you should learn Java, and that's because it is very widely used. Here's an analogy: Back in the day, some people came up with a language called COBOL. If you have any experience with that language, it basically SUCKS (it's gotten better nowadays, but still isn't anywhere near the caliber of modern languages). Why is it still the most used language today then? The banking industry adopted COBOL for their systems, and have been unwilling to change because of the cost of changing.
Java is not a bad language at all, and if you code properly, can write fairly large programs quickly, but it is also one of the main languages used in addition with PHP, HTML/CSS (not really a programming language, but we'll consider it here), Java script, C#/Visual Basic/Other Microsoft developed languages on the web. Not to say you can't get by without learning a lick of Java, but it'll definately make your life easier
And along with what others have said: It's not the amount of time you actually spend coding that's important, it's the amount of time you spend analyzing algorithms/data structures/program flow and logic that are the main keys of being a successful computer scientist (researcher/programmer/developer/tester).
Wow, that was a long rant