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 to JDK 1.7. 
package org.bouncycastle.asn1;

import java.io.IOException;
import java.io.OutputStream;

public class BERSequenceGenerator
    extends BERGenerator
{
    public BERSequenceGenerator(
        OutputStream out) 
        throws IOException
    {
        super(out);

        writeBERHeader(DERTags.CONSTRUCTED | DERTags.SEQUENCE);
    }

    public BERSequenceGenerator(
        OutputStream out,
        int tagNo,
        boolean isExplicit) 
        throws IOException
    {
        super(out, tagNo, isExplicit);
        
        writeBERHeader(DERTags.CONSTRUCTED | DERTags.SEQUENCE);
    }

    public void addObject(
        DEREncodable object)
        throws IOException
    {
        object.getDERObject().encode(new BEROutputStream(_out));
    }
    
    public void close() 
        throws IOException
    {
        writeBEREnd();
    }
}