XPath xpath;

NamespaceContext namepsaceContext=new NamespaceContextImpl(prefix, uri);

xpath.setNamespaceContext(namespaceContext);

public class NamespaceContextImpl implements NamespaceContext{

 public String uri;

 public String prefix;

 public NamespaceContextImpl(){}

 public NamespaceContextImpl(String prefix, String uri){

     this.uri=uri;

     this.prefix=prefix;

    }

 public String getNamespaceURI(String prefix){

   return uri;

 }

 public void setNamespaceURI(String uri){

   this.uri=uri;

 }

 public String getPrefix(String uri){

   return prefix;

 }

 public void setPrefix(String prefix){

   this.prefix=prefix;

 }

 public Iterator getPrefixes(String uri){return null;}

}