When can I say I "KNOW" a programming language?

I'd say if you feel comfortable working in a programming language and know how to do basic to intermediate stuff with it, you know it. Even experienced programmers have to look up stuff online from time to time, like what parameters certain functions take for example.

It depends on what job you're going into as well. If you're applying for a database admin position, obviously you're going to have to know MySQL like no one else and your boss might not care what other languages you know.

I'd say if you're getting A's in your programming classes, after the 2nd semester of programming in that particular language, you should be able to say that you're proficient in that language, if you're getting B's or C's then you need to step up your game a bit

A grade doesn't evaluate what you really know.

Alot of people are self taught, so what does grades matter now?

Google "C++/Java/MySQL interview questions" and see if you can answer them. It also depends on a position you're applying for. Some companies will not even care what language you've used before and will test your general knowledge and problem solving skills (e.g. general programming concepts or provide a solution to given problem in any language).

Good question, I'd like to know the answer also,

I'm Freshman and taking Java 1 at the moment

At what point do you "know" a programming language, you ask?

Unfortunately this is a little bit subjective because programming encompasses a lot of different aspects, with varying levels of expertise, skill and experience.

However we won't go into too much detail and instead skip the fine points and rather generalize a little bit. I would say that most of you knowledge of a programming language is dictated by your ability to solve problems using that language, however this isn't entirely part of the whole picture. Of course you must know the programming fundamentals, and also the basics and intrinsic of how your chosen programming language works (this means things like syntax, object-oriented concepts, functional concepts, etc).

Because there are often so many different ways that you can solve a particular problem (both with any language *and* with the same language), this sort of thing is often hard to answer. Specifics like function parameters are not really applicable to this situation as they are not part of the actual programming language itself, but rather for the end result (for example you may know the C language, however you may not know how to use Win32 COM. Does not knowing how to use COM mean you don't know C, no - of course not!). These things are of course necessary to solving some problems so there is a little bit of a fine line. But for the moment, we need to take helper libraries and APIs out of the picture because it clouds our vision a little bit (how's that for a mixed metaphor!).

In my opinion, if you are comfortable with solving a problem with writing code straight out (i.e. not sourcing it elsewhere, and not copying it), then I believe you have sufficient knowledge of a programming language. It is the knowledge of the concept that is important here - the building blocks of your chosen language and knowing how to piece them together is of critical importance when answering your question.

Hopefully that helps..

Even when you are relatively proficient with a language, there are likely language features that you have missed. These aren't necessarily required to solve a problem but they might make it easier or cleaner. You don't need to know the intricacies of every language feature to be considered proficient for most jobs, but obviously if you're applying for a senior position you will more likely be expected to be competent with many of them. Juniors are pretty much there to learn.

Since I currently just went through this I figure I'll give my two cents. On my resume, I had stated that I was proficient in with Java, HTML, and C#. This is because I know the basics of all the languages and some in depth topics. If you want to say you are proficient with Java, make sure you understand OO concepts like polymorphism, encapsulation, etc. Then I also listed languages I have experience with, such as C++, Assembly, Perl, etc. This way the company knew which programs I was comfortable with and I was still able to show which languages I had used before so I understood the syntax. I received phone interviews from all three places I applied, and ended up getting job offers from 2 of the places.

Another thing to note, when applying for an internship, put your coursework on the resume. List the courses that are you feel are important to the job or developing yourself as a programmer. Example, if you have taken a database course, data mining course, web course, programming course, OS course, then list them on the resume and it will give the employers an idea of what kind of experience you have.