Validate a Zip file with java

[peuplier]

Hello,
Iam looking for how to validate a zip file in java, I tried for that, to use
java.sun.com / j2se / 1.4.2 / docs / ap i/ java / util / zip / CheckedInputStream.html , and in the definition of this class, it is said in the documentation :

An input stream that also maintains a checksum of the data being read. The checksum can then be used to verify the integrity of the input data.

.
I tried this code

public class Checksumoffile 
{
	
public static void Checkyourfiles(String strfilename)
{
	long checksum=0;
	try {
        // Compute Adler-32 checksum
        CheckedInputStream cis = new CheckedInputStream(
            new FileInputStream(strfilename), new Adler32());
        byte[] tempBuf = new byte[128];
        while (cis.read(tempBuf) >= 0) {
        }
        checksum = cis.getChecksum().getValue();
        
    } catch (IOException e) {

}
    System.out.println("The checksum of file is : " + checksum);

}

Called by this code

public static void main(String[] args) {
// TODO Auto-generated method stub
try
{
Checksumoffile.Checkyourfiles(TestStringTokenizing .strchemin2+"/TestHeadFirsts2.zip");
}
catch(Exception exop)
{
System.out.println("Problem using your zip "+ exop.getMessage());

}

I obtained a checksum = 0 in all cases, even when I have tried with a validate file, and a corrupt file.
I think there is a problem for me, either my code is wrong, or I did not understand what checksum and Integrity mean. Do Checksum and Integrity mean the same think ? Are they different ?
I use the almanac java developers 'example availlable here = exampledepot. com / egs / java.util.zip / ChecksumFile.html
Thx for any help.

PS: Despite the fact that I posted two links for the first post, I am not a spammer, Iam a java developper, if I put these two links, this is for a purpose to illustrate, and documented my message. I used to post in several java forum as developpez. com, and java.net forum, Glassfish topic

[angryboy]

seems to work unless file is not found. then checksum = 0.

what's this?
Checksumoffile.Checkyourfiles(TestStringTokenizing .strchemin2+"/TestHeadFirsts2.zip");