Erro no envio de email

Exception in thread “main” java.lang.NoClassDefFoundError: javax/activation/DataSource

at EnviaEmail.enviandoEmail(EnviaEmail.java:25)

at EnviaEmail.main(EnviaEmail.java:42)

public class EnviaEmail{

	public EnviaEmail(){}

	public void enviandoEmail(){
		Properties p = new Properties();		 
		p.put("mail.host", "smtp2.locaweb.com.br");
		Session session = Session.getInstance(p, null);
				
		MimeMessage msg = new MimeMessage(session); 
		
		try{
			msg.setFrom(new InternetAddress("[email removido]"));  
			msg.setRecipient(Message.RecipientType.TO, new InternetAddress("[email removido]"));  
			msg.setSubject("teste");  

			msg.setText("deu certo!");  

			Transport.send(msg);
		}catch (MessagingException e) {
			// TODO: handle exception
		}
	}	
	public static void main(String[] args) {
		EnviaEmail email = new EnviaEmail();

		email.enviandoEmail();

	}
}