Java Database Connectivity (JDBC)

I want to update records in a table that has a Date data type field. It's a oracle databse. I use the oracle thin drive to connect to the database. The everything works well, only when i try to update records that have date type value, something doesn't work.

I use the following stmt to update DB:
//**************************************
Class.forName("oracle.jdbc.driver.OracleDriver");
Conn = DriverManager.getConnection("jdbc:oracle:thin:@hostname:portnumber:schname", "uid","pwd");
stmt=Conn.createStatement();
String updStr = "UPDATE Article SET Archive = ' Disable' WHERE ArticleDate = # " + sqlDate +"# " ;
stmt.executeUpdate( updAStr ) ;
//**************************************

But I always got the SQLException run time error, which is "ORA-00911: invalid character"

Who can help me to find out how to write the above Update statement correctly? esp. that how to present the Date type variable in the statement.!
BTW, sqlDate is a Java.sql.Date variable, Is it "# " + sqlDate + "# " the right way?

Many thanks