Error when applet is trying to connect to WLS server

Question

Hello everyone,
I'm currently having problems with applets and WebLogic. Though I know, applets are not the most appreciated way to do things with weblogic (or even in general), there are no real alternatives for us.
We have a larger application consisting of several servlets, already integrated into WLS and using the data sources.
Now we want to create a small piece of applet that uses WLS to get data from the same JDBC data sources to display and navigate inside charts. These might even be updated on a regular basis while the applet is running.
So, there are two questions:
First, is it possible for the applet to be available on the server and connect to WLS by creating an initial context? I'm currently trying and i get an "java.security.AccessControlException: access denied (java.lang.RuntimePermission setContextClassLoader)". See the attached code below to see the connection example.
Second, if i can connect to the WLS, will this also be possible when the WLS is not localhost anymore, but another server? To clarify, an example:
Can an applet that is running inside a WLS at "http://theotherserver.net:7001/myapp/MyApplet.class" connect to the WLS at "theotherserver.net"?
I'd be glad if anyone could help me with that. The code I'm currently using (inside the init() function of the applet), is the following:
public void init() {
     Context ctx = null;
     Hashtable<String, String> ht = new Hashtable<String, String>();
     ht.put(Context.INITIAL_CONTEXT_FACTORY, "weblogic.jndi.WLInitialContextFactory");
     ht.put(Context.PROVIDER_URL, "t3://localhost:7001");
     try {
          ctx = new InitialContext(ht);
     // Use the context in your program
          System.out.println("context success");
     } catch (NamingException e) {
     System.out.println("NamingException"); // a failure occurred
     e.printStackTrace();
     } catch (AccessControlException e) {
          System.out.println("security control exception when authing"); // a failure occurred
          e.printStackTrace();
     } catch (Exception e) {
          System.out.println("other exception"); // a failure occurred
          e.printStackTrace();
     } finally {
          System.out.println("finally");
          try {
               ctx.close();
               System.out.println("close");
          } catch (Exception e) {
               System.out.println("close exception"); // a failure occurred
When the applet is run, whatever I do in start() etc get's done (for example drawing charts with jfreechart), but the java console prints the following as a result of the failed connection to WLS:
security control exception when authing
java.security.AccessControlException: access denied (java.lang.RuntimePermission setContextClassLoader)
     at java.security.AccessControlContext.checkPermission(Unknown Source)
     at java.security.AccessController.checkPermission(Unknown Source)
     at java.lang.SecurityManager.checkPermission(Unknown Source)
     at java.lang.Thread.setContextClassLoader(Unknown Source)
     at weblogic.corba.j2ee.naming.ORBHelper.createORB(ORBHelper.java:426)
     at weblogic.corba.j2ee.naming.ORBHelper.getORBReferenceWithRetry(ORBHelper.java:571)
     at weblogic.corba.j2ee.naming.ORBHelper.getORBReference(ORBHelper.java:547)
     at weblogic.corba.j2ee.naming.InitialContextFactoryImpl.getInitialContext(InitialContextFactoryImpl.java:85)
     at weblogic.corba.j2ee.naming.InitialContextFactoryImpl.getInitialContext(InitialContextFactoryImpl.java:31)
     at weblogic.jndi.WLInitialContextFactory.getInitialContext(WLInitialContextFactory.java:41)
     at javax.naming.spi.NamingManager.getInitialContext(Unknown Source)
     at javax.naming.InitialContext.getDefaultInitCtx(Unknown Source)
     at javax.naming.InitialContext.init(Unknown Source)
     at javax.naming.InitialContext.<init>(Unknown Source)
     at com.igrafx.charter.program.CharterApplet.init(CharterApplet.java:70)
     at sun.applet.AppletPanel.run(Unknown Source)
     at java.lang.Thread.run(Unknown Source)
finally
close exception
Edited by: user10921034 on 11.11.2009 09:46

Answer 1

I have solved the above problem now. The problem was, that I only signed my own jar, but not the wlclient.jar, which also needs the rights to instantiate classes.
This also solved my second question. Yet, there is another thing, now that I am trying to use JNDI to access a JDBC shared datasource from weblogic.
The data source is accessible and working (tested from servlets). Now I'm trying to create a connection with the following code, but it does not get past the first lookup:
try {
DataSource ds = (DataSource) this.appletContext.lookup("ReportCentral");
conn = ds.getConnection();
conn.setAutoCommit(true);
The thrown exception:
java.lang.NoClassDefFoundError: weblogic/jdbc/common/internal/RemoteDataSource
     at java.lang.ClassLoader.defineClass1(Native Method)
     at java.lang.ClassLoader.defineClass(Unknown Source)
     at java.security.SecureClassLoader.defineClass(Unknown Source)
     at java.net.URLClassLoader.defineClass(Unknown Source)
     at java.net.URLClassLoader.access$000(Unknown Source)
     at java.net.URLClassLoader$1.run(Unknown Source)
     at java.security.AccessController.doPrivileged(Native Method)
     at java.net.URLClassLoader.findClass(Unknown Source)
     at java.lang.ClassLoader.loadClass(Unknown Source)
     at java.lang.ClassLoader.loadClass(Unknown Source)
     at java.lang.ClassLoader.loadClassInternal(Unknown Source)
     at java.lang.Class.forName0(Native Method)
     at java.lang.Class.forName(Unknown Source)
     at sun.rmi.server.LoaderHandler.loadClass(Unknown Source)
     at sun.rmi.server.LoaderHandler.loadClass(Unknown Source)
     at java.rmi.server.RMIClassLoader$2.loadClass(Unknown Source)
     at java.rmi.server.RMIClassLoader.loadClass(Unknown Source)
     at com.sun.corba.se.impl.util.JDKBridge.loadClassM(Unknown Source)
     at com.sun.corba.se.impl.util.JDKBridge.loadClass(Unknown Source)
     at com.sun.corba.se.impl.javax.rmi.CORBA.Util.loadClass(Unknown Source)
     at javax.rmi.CORBA.Util.loadClass(Unknown Source)
     at com.sun.corba.se.impl.presentation.rmi.StubFactoryFactoryStaticImpl.createStubFactory(Unknown Source)
     at com.sun.corba.se.impl.encoding.CDRInputStream_1_0.read_Object(Unknown Source)
     at com.sun.corba.se.impl.encoding.CDRInputStream_1_0.read_Object(Unknown Source)
     at com.sun.corba.se.impl.encoding.CDRInputStream.read_Object(Unknown Source)
     at com.sun.corba.se.impl.corba.TCUtility.unmarshalIn(Unknown Source)
     at com.sun.corba.se.impl.corba.AnyImpl.read_value(Unknown Source)
     at com.sun.corba.se.impl.encoding.CDRInputStream_1_0.read_any(Unknown Source)
     at com.sun.corba.se.impl.encoding.CDRInputStream.read_any(Unknown Source)
     at weblogic.corba.cos.naming._NamingContextAnyStub.resolve_any(_NamingContextAnyStub.java:81)
     at weblogic.corba.j2ee.naming.ContextImpl.lookup(ContextImpl.java:208)
     at weblogic.corba.j2ee.naming.ContextImpl.lookup(ContextImpl.java:168)
     at javax.naming.InitialContext.lookup(Unknown Source)
     at com.igrafx.charter.program.CharterApplet.start(CharterApplet.java:178)
     at sun.applet.AppletPanel.run(Unknown Source)
     at java.lang.Thread.run(Unknown Source)
I cannot find the mentioned class, to include it in my jar, neither am I sure that this is the best way to get a connection to the database this way.
In the applet, it is NOT possible to create the connection by hand, as the user/password are only available to weblogic, but not the overlying J2EE applications.
If i do that on my local system, nevertheless, it works:
OracleDataSource ds = new OracleDataSource();
ds.setURL("jdbc:oracle:thin:...@localhost:1521:XE");
conn = ds.getConnection();
This creates a valid connection.
So, the major question is: How can I access the connection pool of Weblogic through an applet?