If you want to do the drawing in Java, consider using a chart drawing library. E.g.

http://www.jfree.org/jfreechart/index.html

gets recommended often. The web site also has a list of other chart libraries.

If you just have to plot some (scientific) data, and if you can live with an external C program, consider using gnuplot

http://www.gnuplot.info/

Use System.exec() to pipe the plot commands and data into gnuplot, or just write the data to a file and use gnuplot separately.