Applets + JDBC + MySQL = access denied

[Lucas Mello]

Hello all.

I'm getting the following error when trying to run my applet:

com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception: 

** BEGIN NESTED EXCEPTION ** 

java.security.AccessControlException
MESSAGE: access denied (java.net.SocketPermission Server resolve)

STACKTRACE:

java.security.AccessControlException: access denied (java.net.SocketPermission Serverresolve)
	at java.security.AccessControlContext.checkPermission(Unknown Source)
	at java.security.AccessController.checkPermission(Unknown Source)
	at java.lang.SecurityManager.checkPermission(Unknown Source)
	at java.lang.SecurityManager.checkConnect(Unknown Source)
	at sun.plugin2.applet.Applet2SecurityManager.checkConnect(Unknown Source)
	at java.net.InetAddress.getAllByName0(Unknown Source)
	at java.net.InetAddress.getAllByName(Unknown Source)
	at java.net.InetAddress.getAllByName(Unknown Source)
	at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:246)
	at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:271)
	at com.mysql.jdbc.Connection.createNewIO(Connection.java:2771)
	at com.mysql.jdbc.Connection.<init>(Connection.java:1555)
	at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:285)
	at java.sql.DriverManager.getConnection(Unknown Source)
	at java.sql.DriverManager.getConnection(Unknown Source)
	at Game.init(Game.java:80)
	at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Unknown Source)
	at java.lang.Thread.run(Unknown Source)


** END NESTED EXCEPTION **

The code is:

		try {
			Class.forName("com.mysql.jdbc.Driver").newInstance();
		} catch(Exception connectException) {
		connectException.printStackTrace();
		}

		try {
			Connection con = DriverManager.getConnection
                                                ("jdbc:mysql://Server:3306/db?user=user&password=password");
			Statement stmt = con.createStatement();
			ResultSet rs = stmt.executeQuery(query);

			stmt.close();
			con.close();

		} catch(SQLException ex) {
		                ex.printStackTrace();
		}

I spent some hours googling stuff, but it was useless.
I think that the problem may be that the database server is different from the page server.
I also came with results about signing applets. Will signing my applet help?

[Paul Clapham]

Lucas Mello wrote:I think that the problem may be that the database server is different from the page server.
I also came with results about signing applets. Will signing my applet help?

If that's true (about the servers) then yes, signing the applet should help.

[VineetK Singh]

Lucas

You need to sign your applet. Either self sign it or obtain a certificate from authorized agency like Verisign.