Java.lang.NoClassDefFoundError ao acessar do driver

package teste;

import java.sql.DriverManager;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;

public class AcessaBanco{
	Connection conn = null;
	ResultSet  rs ;
	String query = "select * from ca_usuarios"; 
	
	public static void main(String[] args) throws SQLException, ClassNotFoundException {
		try {
			Class.forName ("oracle.jdbc.OracleDriver");
			
	//	} catch (SQLException e) {
	//		System.out.println("Não existe driver " );
		}  catch (ClassNotFoundException e) {
			System.out.println("Não existe driver " );
		}			
	}
}