i need to know how to create a program draw a graph once i insert a linear programming equations can it be done by java???how???

yes I believe it can be made.
usually, one makes it by analysing the problem, coding the software and then entering the equations

first thanks for your answer but i need to know which class can be imported to draw such an inequality.

Here you can find free code to make graphs in Java. don't know whether or not you can input equations, maybe you'll still have to write that part for yourself.

I also never used this code before, so I can't really tell how good it works, or how easy it is to implement