You can add a grid line at any position in the chart. The grid line can have a label and any color.
<applet code=com.objectplanet.chart.BarChartApplet
archive=chart.jar width=300 height=200>
<param name=sampleValues value="100,200,300,400,500">
<param name=targetValueLine_0 value="Target A, 150, red">
<param name=targetValueLine_1 value="Target B, 350, blue">
<param name=targetValueLine_2 value="Target C, 500, magenta, value">
</applet>
<applet code=com.objectplanet.chart.BarChartApplet
archive=chart.jar width=300 height=200>
<param name=sampleValues value="100,200,300,400,500">
<param name=targetValueLine_0 value="Target A, 150, red">
<param name=targetValueLine_1 value="Target B, 350, blue">
<param name=targetValueLine_2 value="Target C, 500, magenta, value">
<param name=barAlignment value=horizontal<
</applet>