In Bernoulli's theoram as stream lines cannot intersect each other and even water is nearly incomprehensible then how is it possible to all the water which got in come out, eg 100 stream lines goes in from one side then 100 stream lines should come out the other end whereas the area is decreased and even water is incomprehensible
Stream lines have no radial dimension (width).
You can keep squishing them infinitely close together, because they just describe the motion of the fluid.
What you describe does have implications for continuity though. Since mass flow has to stay the same (no mass being created/destroyed), if the area decreases, the fluid must move faster. That is to say that the spacing between the lines would have an effect on the velocity of the fluid.