Are you unsure of your career objective?
You need to know your objective in order to get the right match between yourself and the dream job you want to land. In other words, if you do not get a clear picture of what you want to do in life, there is no way you can carve a proper and definite path for yourself professionally. Hence, it is good and important in the long run to know where you are going; then only you can choose the right stepping stones.
However, in case you are young and undecided you can still have a short-term objective instead of a long term. Your short-term objective should be anything except monetary benefit (which though it is high on everyone's mind looks very shallow on the CV). Hence, you could say that you want to gain experience in a particular field, or understand a particular industrial functioning and see the fit, etc
Your objective should be a close match to the overall objective of the job you are applying for, hence whenever you are applying for a job the objective should be slightly modified to exactly fit that particular job. Do not under any circumstance state that the objective is undecided. Such an answer will show complete immaturity and will definitely invite summary rejection.
The CV should always reflect that you are in control and I am sure you can understand how important is the objective to show that you are in control. Otherwise you will seem like a driver who is rearing to go, but has no exact destination. The company would feel threatened to use such talent as there is no guarantee that they would be satisfied and/or will stick to the job for a long period (or at least a reasonable period of time).
There are many other way to deflect the prospective employer from the lack of objective - i.e. by highlighting the skills match to that of the job. However, for a veteran employer such tricks would not hold much water. Hence, be prepared to answer a few long questions on this aspect when you make it for the interview.
It is best for those who have deep doubt of what exactly out of their professional life, not to mention it at all. There are CV formats which allow for this, but its absence from the CV may ensure that it would be asked during the interview for which you should be carefully prepared.
To summarize, state an objective only when you have totally internalized it; state short-term objective when you do not have long-term objectives; customize each objective to fit exactly each job you are applying for.
