You can customize your applets by providing parameters at runtime in. But it is a good practice to always provide default values, when specific values for parameters are not provided.

You can do this by checking for null values and/or proper type checking (if you expect numeric or date values). Here is the code:

 public class MyApplet extend Applet {         public void  init(){          // Get the Parameter	  String  frameTitle = getParameter("FRAME_TITLE");	  // Check for Null	   if (frameTitle  == null) {	       // Provide Default value	        frameTitle = "Frame to Test Parameters";	   }	  String frameWidthString = getParameter("FRAME_WIDTH");	  int   frameWidthInt = 0;	  try{	        frameWidthInt =  Integer.parseInt(frameWidthString);	  } catch(Exception ex){	       // Catch Exception if frameWidthString is null or invalid value               // Default value	       frameWidthInt = 100;	  }	  String frameHeightString = getParameter("FRAME_WIDTH");	  int   frameHeightInt = 0;	  try{	        frameHeightInt =  Integer.parseInt( frameHeightString );	  } catch(Exception ex){	       // Provide Default Value	       frameHeightString = 100;	  }	 Frame f = new Frame(frameTitle);	 f.setSize(frameWidthInt,frameHeightString);	 f.show();         }}