Is hanja still used in Korea?

Koreans do you know any hanja?

Technically yes, but not as much as it used to be.
My parents began to learn Hanja(Chinese characters) from the 3rd grade or so, however, I began to learn Hanja in high school.
My parents probably know Chinese characters 10 times more than me.
When I was 6 or 7(almost 20 years ago), newspapers used Hanja a lot in their article, so I often asked my dad how to read this word and that word blah blah...
Thesedays, however, newspapers hardly use Chinese characters and even if they do, they always print Hangul with it.
e.g. 甑(鍦嬫皯)霌れ潃 鞝曥箻(鏀挎不)鞚?鞎堨爼鞚?鞖办劆霅橁赴毳?..

Learning Hanja is required in most high schools and knowing many Hanja is very useful to study further in higher education or to get a better job.
Therefore, Koreans know Hanja.

Note: We don't mix-use Chinese characters in our daily life while Japanese use Kanji in their everyday life.

Many Korean names are still made in Chinese characters.
Most people(high school graduate) know how to write their names in Hanja.
Also

Yes, I know some of them and high/middle(?) school students are required to learn them, I think.
It's very helpful when you're trying to find the meaning of a word you've never seen before. It's almost like learning Latin for English.

It's not completely gone from Korea, and it never will be. You can still survive in Korea without knowing any of them, but you might not get some of the jokes, signs, puns, etc.

they soetimes use...

I am learnign Korewan and i know hanja also.....
about 500 or something like that....
Ok maybe more than 500
but i have not couted....

瀹夊頃橃劯鞖?br> 雮橂姅 闊撳湅瑾炿ゼ 鐔卞績頌?宸ュか頃╇媹雼?
楹掗簾鞚€ 鍋夊ぇ頃?鍕曠墿鞚措嫟

Yes, I learned hanja from 6th grade and hanja is still mandatory in middle school and maybe highschool, too.
They still have to learn hanja since many of the words in Korean and in Korean literature are hanja.