[quote author=Fu-Kwun Hwang link=topic=1400.msg5269#msg5269 date=1262878630]
1. The jar (in your attached zip)  did not contain any compiled java class file.
2. The first java code is
package com.jhlabs.image;
It means that ConvolveFilter.java should be under com\jhlab\image directoory

public class ConvolveFilter extends AbstractBufferedImageOp {
It means that , AbstractBufferedImageOp.java is also required,
and AbstractBufferedImageOp.java need to be compiled before you can compile ConvolveFilter.java

When AbstractBufferedImageOp.class and AbstractBufferedImageOp.class are available.
Those files need to be packed into a jar file.
This is new to me. Ok so the morale of the story is look for the jar file.
Ok i managed to import the filter.jar but how do i call the function ConvolveFilter () or how to know what to call it ; ???
i go see how u did it in the EJS version of Fourier Synthesis (You can hear the sound,too!) http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=1073.0

[quote author=Fu-Kwun Hwang link=topic=1400.msg5269#msg5269 date=1262878630]
I found the filter.jar which contains all the filter at that web site.
Use it in the EJS ,remember to add import [b]com.jhlabs.image.*[/b] in the option page ,
and it should work now.
Yes, i also follow your lead n found it here