JDBC Connection

[improvcornartist]

This worked fine the first time I ran it. The next day, it couldn't connect. It looks like MySQL drops the connection during the night, and then I can't get it back. My question is, is there something wrong in my code, or is the error due to the way the server handles the connection?

//code snippet
public class MyClass{
  InitialContext ic;
  DataSource ds;
  Connection conn;
  PreparedStatement stmt;
  ResultSet rs;
 
  public void Init(){ //called when application initializes
    try{
        ic = new InitialContext();
        ds = (DataSource)ic.lookup("jdbc/MyDB"); //MySQL db
    } catch (Exception e){log(e);}
  }
 
  public void Exit(){ //called when application closes
    closeAll();
  }
 
  public void closeAll(){
    try{
        if(rs != null){rs.close();}
        if(stmt != null){stmt.close();}
        if(conn != null){conn.close();}
    }
    catch(SQLException e){log(e);}
    catch(Exception e){log(e);}
  }
 
  public void loadIDs(){ //called by user action
    try{
        conn = ds.getConnection();
        stmt = conn.prepareStatement("SELECT id FROM mytable WHERE id > ?;");
        stmt.setInt(1, x); //x comes from elsewhere
        rs = stmt.executeQuery();
        while(rs.next()){/* list ids */}
    }
    catch(SQLException e){log(e);}
    catch(Exception e){log(e);}
    finally{closeAll();}
  }
  // other methods access database similar to loadIDs
}

Partial error:
No operations allowed after connection closed.Connection was implicitly closed due to underlying exception/error:
** BEGIN NESTED EXCEPTION ** com.mysql.jdbc.CommunicationsException MESSAGE: Communications link failure due to underlying exception:
** BEGIN NESTED EXCEPTION ** java.net.SocketException MESSAGE: Software caused connection abort: socket write error