While packaging the Web Application DefaultWebApp for
deployment into the WebLogic server, the home and remote
interfaces of the enterprise beans used by the servlets
should reside in which directory?
a. DefaultWebApp/META_INF/classes
b. DefaultWebApp/META_INF/lib
c. DefaultWebApp/WEB_INF/lib
d. DefaultWebApp/WEB_INF/classes
e. DefaultWebApp/classes
Choice D is correct. When packaging a web application
create META-INF and WEB-INF subdirectories in the
application directory to hold deployment descriptors and
compiled Java classes. All servlet classes and helper
classes should reside in the WEB-INF/classes
subdirectory. The home and remote interface classes for
enterprise beans used by the servlets into the
WEB-INF/classes subdirectory.
All the HTML files, JSP files, images, and any other
files that these Web pages reference should exist in the
application directory, maintaining the directory
structure for referenced files. The META_INF directory
contains the deployment descriptors for the enterprise
beans, but not the classes.
How do I set up my CLASSPATH?
Setting up your CLASSPATH correctly depends on what you
are trying to do. The most common tasks are described
below:
* Starting WebLogic Server. See Setting the Classpath
Option in the Starting and Stopping WebLogic Servers
section of the Administration Guide. In addition, your
WebLogic distribution includes shell scripts that you
can use to start the server. These scripts, which are
located in the domain directories under the config
directory of your WebLogic Server distribution,
automatically set up the CLASSPATH variable in the shell
before starting the server.
Why do I get the following exception when viewing the
JNDI tree?
isSerializable(class.javax.naming.Binding)
java.io.NotSerializableException:
java.io.PrintWriter at
java.io.ObjectOutputStream.OutputObject
The Weblogic Server JNDI implementation requires objects
to be serializable, not referencable. A PrintWriter
cannot be serialized and therefore should be declared
transient.
When deploying a resource adapter (.rar) to WebLogic
Server, are its classes placed in the WebLogic classpath?
For instance, I am deploying an EJB and a resource
adapter (.rar), the EJB has no dependencies on the .rar
because the EJB is writing to the common client
interface (CCI). The EJB client application has
sends/marshals as parameter classes that are defined in
the .rar. For some reason the EJB's class loader
hierarchy cannot find the definition of this .rar-specific
class, even though the .rar is deploying successfully. I
receive the following error on the EJB client:
java.rmi.UnmarshalException: error unmarshalling
arguments; nested
exception
is:
java.lang.ClassNotFoundException:
com.mycompany.InteractionSpecImpl
When you pass an instance of
com.myclientcompany.server.eai.InteractionSpecImpl as an
argument to your EJB, the appServer needs to
de-serialize (unmarshal) the object under the EJB
context, and it needs the required class for
unmarshalling, inside the ejb-jar(raTester.jar). So if
you include the interactionspecimpl class in your ejb-jar
file, then you do not need to include those classes in
your server's classpath.
How is security handled in the WebLogic J2EE Connector
Architecture?
Due to the fact that the current configuration and
packaging requirements for resource adapters in WebLogic
Server require the hand-editing of the weblogic-ra.xml
file, any new passwords specified in the
security-principal-map entries are done in clear-text.
BEA understands the importance of protecting security
passwords. Hence, we provide a Converter Tool that
allows for the encryption of all passwords present in
the weblogic-ra.xml file. The Converter Tool is shipped
in the standard weblogic.jar file.
Can I enable requests to a JDBC connection pool for a
database connection to wait until a connection is
available?
No, there's no way to allow a request to wait for a pool
connection, and from the system point of view there
should not be. Each requests that waits for a connection
ties up one of the fixed number of execute threads in
the server, which could otherwise be running another
server task. Too many waiting requests could tie up all
of the execute threads and freeze the server.
How do I use multibyte character sets with WebLogic
jDriver for Informix?
Currently, multibyte character sets are not supported
for the WebLogic jDriver for Informix driver.
How do I connect to an SQL Server instance that is
running on a machine with multiple instances of SQL
Server 2000?
Each instance of MS SQL Server must be listening on a
different port. So, you can use the port number in the
properties that you pass to the getConnection() method
or, in case of connection pools, you can specify the
port property in the following properties:
server=machineName
port=instancePort
To find the port number where each MS SQL Server
instance is running, run the server network utility (in
the Microsoft SQL Server program group), select the
server instance, select TCP/IP, and click the properties
button.
Why does FOR UPDATE in Oracle 8 cause an ORA-01002
error?
The Oracle 8 server generates an ORA-01002:fetch out of
sequence error message when you use a FOR UPDATE
statement with AUTOCOMMIT turned on (which is the
default state when using JDBC). This is known to happen
on Oracle 8.0 and 8.1 on Solaris and on Oracle 8.1 on
Windows NT. If you turn AUTOCOMMIT off, you will not
receive this error. Because this problem is due to a
change in the Oracle 8 server, you should contact Oracle
support for more information.
What causes an OCIW32.dll error?
You may receive the following error message when using
your JDBC driver for Oracle: "The ordinal 40 could not
be loaded in the dynamic link library OCIW32.dll." This
problem is caused by an out-of-date version of
OCIW32.DLL in your system directory. Some programs
install this file in the system directory in order to
run. If you remove this file from the system directory
you should no longer receive this error.
What transaction isolation levels does the WebLogic
jDriver for Oracle support?
Your servlet application may use Oracle Thin Drivers to
access a database that includes BLOB fields. If you
install and try to use WebLogic jDriver for Oracle and
the same code fails and produces an exception similar to
the following:
com.roguewave.jdbtools.v2_0.LoginFailureException:
TRANSACTION_READ_UNCOMMITTED isolation level not allowed
The Stack Trace:
com.roguewave.jdbtools.v2_0.LoginFailureException:
TRANSACTION_READ_UNCOMMITTED isolation level not allowed
at
com.roguewave.jdbtools.v2_0.jdbc.JDBCServer.createConnection
(JDBCServer.java :46)
at
com.roguewave.jdbtools.v2_0.ConnectionPool.getConnection_
(ConnectionPool.jav a:412)
at
com.roguewave.jdbtools.v2_0.ConnectionPool.getConnection
(ConnectionPool.java :109)
Setting the Isolation_level to 1 in the code that calls
the RogueWave JDBCServer class works with the Oracle
thin driver but fails with WebLogic jDriver for Oracle.
WebLogic jDriver for Oracle supports the following
transaction isolation levels:
SET TRANSACTION ISOLATION LEVEL READ COMMITTED
SET TRANSACTION ISOLATION LEVEL SERIALIZABLE
According to the Oracle documentation, the Oracle DBMS
only supports these two isolation levels. Unlike other
JDBC drivers, WebLogic's drivers throw an exception if
you try to use an isolation level that is unsupported.
Some drivers silently ignore attempts to set an
unsupported isolation level. WebLogic suggests testing
whether the Oracle thin driver is not just ignoring
settings for unsupported isolation events.
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