Java.util.jar.JarEntry class in Java

//Java program demonstrating JarEntry method
import java.io.FileInputStream;
import java.io.IOException;
import java.io.PrintStream;
import java.util.jar.JarEntry;
import java.util.jar.JarInputStream;
class JarEntryDemo
{
    public static void main(String[] args) throws IOException 
    {
        FileInputStream fis = new FileInputStream("codechecker.jar");
        JarInputStream jis = new JarInputStream(fis);
        JarEntry je=jis.getNextJarEntry();

        PrintStream out = System.out;

        //illustrating getAttributes
        out.println(je.getAttributes());

        //illustrating getCodeSigner
        out.println(je.getCodeSigners());

        //illustrating getCertificates
        out.println(je.getCertificates());
    }
}

//Java program demonstrating JarEntry method
package java.util.jar;
  
 import java.io.IOException;
 import java.util.zip.ZipEntry;
 import java.security.CodeSigner;
 import java.security.cert.Certificate;

 public class JarEntry extends ZipEntry
 {
    Attributes attr;
    Certificate[] certs;
    CodeSigner[] signers;
 
    public JarEntry(String name) 
    {
        super(name);
    }
 
    public JarEntry(ZipEntry ze) 
    {
        super(ze);
    }
  
    public JarEntry(JarEntry je)
    {
        this((ZipEntry)je);
        this.attr = je.attr;
        this.certs = je.certs;
        this.signers = je.signers;
    }
  
    public Attributes getAttributes() throws IOException 
    {
      return attr;
    }
  
    public Certificate[] getCertificates() 
    {
        return certs == null ? null : (Certificate[]) certs.clone();
    }
  
    public CodeSigner[] getCodeSigners() 
    
    {
        return signers == null ? null : (CodeSigner[]) signers.clone();
    }
}