A bit stuck with my small database design

[Kristjan Toots]

Hello.
I'm fairly new to the programming and I am still facing difficulties with OOP based concepts. I am trying to build a small standalone swing application with some database functions. I would be thankful for any kind of pointers and I appreciate any discussion on topic.

What I have so far:
I had in mind that I would create Database class what is responsible for starting my hsql server & making connection to it. Then I thought I would create a separate class where I do all the writing and reading from. Am I going towards the right direction? I've read about MVC design pattern but I can't apply it here can I?

I tried to play around with private static Connection connection object. I thought that when I make it static there would be only one of those. So I could pass that to different class and in such way I can accomplish doing writing / reading from separate class. Ended up with
Server@8813f2]: [Thread[HSQLDB Server @8813f2,5,main]]: run()/openServerSocket():
java.net.BindException: Address already in use: JVM_Bind



I've created Database class like this:

public class Database {
   private static Server hsqlServer = null;
   private static Connection connection = null; 
   private String databaseName;
   private String databasePath;

   public Database() {
      databaseName = "xdb";
      databasePath = "file:testdb2";
   }

   public void startServer() {
      if (hsqlServer == null) {
         try {
         hsqlServer = new Server();
         hsqlServer.setLogWriter(null);
         hsqlServer.setSilent(true);
         hsqlServer.setDatabaseName(0, databaseName);
         hsqlServer.setDatabasePath(0, databasePath);

         hsqlServer.start();
         System.out.println("Server started.");

         } catch (Exception e) {
            e.printStackTrace();
         }
         } else {
            System.out.println("Database already running...");
         }
   }
  
 public void stopServer() {
      if (hsqlServer != null) {
         hsqlServer.stop();
         System.out.println("Server stopped.");
         }
   }

   public Connection getConnection() {
      try {
         Class.forName("org.hsqldb.jdbcDriver");
         connection = DriverManager.getConnection("jdbc:hsqldb:hsql://localhost/xdb", "sa", "");

         System.out.println("Connection established...");
         return connection;

         } catch (ClassNotFoundException e) {
            e.printStackTrace();
         } catch (SQLException e) {
            e.printStackTrace();
         }
         return null;
   }

   public void closeConnection() {
      try {
         connection.close();
      } catch (SQLException e) {
         e.printStackTrace();
      }
         System.out.println("Connection closed successfully");
   }
	
   public void isConnection() {
      if(connection != null) {
         System.out.println("There is still a valid connection");
      }
   }
}

[Paul Clapham]

So why did you only make those two variables static? Why aren't the other two variables static, for the same reason? And the methods which use those variables, why aren't they static?

[Kristjan Toots]

Paul Clapham, thank you for your reply.
I don't know why I forgot to make those methods static aswell, anyway, your kind guidance steered me towards a solution.

I remember from somewhere that using a lot of static methods is not recommended. Now, when I have static methods all over the place I don't feel so pleased about my approach like I thought I would.

I'm thankful for suggestions how I should rearrange things. : )