#1 is grammatically possible, but feels strange. More likely would be something like "By the time I am 40, I will have been working hard in journalism for twenty years". The "for twenty years" helps to "complete" an idea that otherwise seems unfinished.
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magixo By the time I am 40, I will be working hard in journalism.Without the extra information -- as mentioned in the previous post -- you'll need this one.
AnonymousBy the time I am 40, I would have been working hard in journalism.- will be the correct one I guessNo. You guessed wrong. I am doesn't go with would have been.