http://www.bouncycastle.org/java.html: The Bouncy Castle Crypto package is a Java implementation of cryptographic algorithms. This jar contains JCE provider and lightweight API for the Bouncy Castle Cryptography APIs for JDK 1.5. 
package org.bouncycastle.jce.exception;

import java.security.cert.CertPath;
import java.security.cert.CertPathBuilderException;

public class ExtCertPathBuilderException
    extends CertPathBuilderException
    implements ExtException
{
    private Throwable cause;

    public ExtCertPathBuilderException(String message, Throwable cause)
    {
        super(message);
        this.cause = cause;
    }

    public ExtCertPathBuilderException(String msg, Throwable cause, 
        CertPath certPath, int index)
    {
        super(msg, cause);
        this.cause = cause;
    }
    
    public Throwable getCause()
    {
        return cause;
    }
}