Hi ppl, I have taken this prog. from a ref. book. this prog. compiles OK but as the Applet is coming up on the screen it says(in the lower most line) of the appletviewer..Applet not initialised.. Same problem when I run it on the Netscape Browser...in that case it says "Applet cant start :ERROR". Dont forget to see the error that pops on the DOSpromot HELP SOON....EXAM VERY CLOSE AND JUST A BEGINNER........ import java.awt.*; import java.applet.*; import java.lang.*;
public class BarChart extends Applet { String laabel[]; int n = 0; int value[]; public void init() { try { n = Integer.parseInt(getParameter("columns")); laabel[0] = getParameter("Label1"); laabel[1] = getParameter("Label2"); laabel[2] = getParameter("Label3"); laabel[3] = getParameter("Label4"); value[0] = Integer.parseInt(getParameter("c1")); value[1] = Integer.parseInt(getParameter("c2")); value[2] = Integer.parseInt(getParameter("c3")); value[3] = Integer.parseInt(getParameter("c4")); } catch (NumberFormatException e) {} }
public void paint(Graphics g) { for(int i = 0; i<n ; i++)> { g.fillRect(50,i*20 + 10,value[i],20); g.drawString(laabel[i], 20, i*30 + 10); } } } /* <HTML> <HEAD> </HEAD> <BODY> <APPLET> CODE = BarChart.class WIDTH = 100 HEIGHT =300> <PARAM NAME = "columns" VALUE = "4"> <PARAM NAME = "Label1" VALUE = "90"> <PARAM NAME = "Label2" VALUE = "91"> <PARAM NAME = "Label3" VALUE = "92"> <PARAM NAME = "Label4" VALUE = "94"> <PARAM NAME = "c1" VALUE = "110"> <PARAM NAME = "c2" VALUE = "200"> <PARAM NAME = "c3" VALUE = "50"> <PARAM NAME = "c4" VALUE = "80"> </APPLET> </BODY> </HTML> */ //this is the error in DOS Prompt java.lang.NullPointerException: at BarChart.init(BarChart.java:19) at sun.applet.AppletPanel.run(Compiled at java.lang.Thread.run(Thread.java:47
See, you have just declared the String array, but you haven't constructed it!! Change that line to String laabel[] = new String[4]; The same problem will crop up for your value array also. Change that to int value[] = new int[4]; Regards, Suresh.
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