Access Database in Servlet

Always use PreparedStatement and Password is reserved keyword in Ms-Access.

  boolean userFound=false;

  conn=DriverManager.getConnection("jdbc:odbc:FBS");
  String sql="select [UserName],[Password] from user_login 
                            where [UserName]=? and [Password]=?";
  PreparedStatement st=conn.prepareStatement(sql);
  st.setString1(1,userName);
  st.setString1(2,password);
  rs=st.executeQuery();

  if(rs.next())
   {
    userFound=true;
   }
  st.close();
  conn.close();

 if(userFound)
  {
  }

Two things jump out at me.

The first is that in the init, you should only have to call

Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");

without an additional "newInstance()". In fact, if you're using a JRE that supports JDBC 4.0, you shouldn't even need the "Class.forName(...)" call

The second is that you should only need the double slashes to escape forward slashes in the path. Try changing the connection string to:

conn=DriverManager.getConnection("jdbc:odbc:FBS={Microsoft Access Driver(*.accdb)};DBQ=C:\\Users\\Dumbre\\Documents\\NetBeansProjects\\Flat Booking System\\Flat_System.accdb;");

Additionally, you might try switching to a DSN, just for testing. Create a system DSN and your connection string should be:

jdbc:odbc:TheNameForTheNewDSNThatYouJustCreated

Well, obviously that last part has to be the actual name.