Posts Tagged ‘Java’

Recent history

BEA WebLogic 9.0, 9.1 and 9.2 were released from 2007: the main features were: a new console, WLST (WebLogic ScriptingTool), deployment plans, WebLogic Diagnostic Framework (WLDF), new security providers (RDBMS, SAML 1.1, etc.), JMS performance improvements, support of Java EE 4, JDK 5, Spring, OpenJPA, Kodo, etc.

Since this date, some events happened:

• Oracle bought Sun (2009)
• Oracle released WebLogic 10.3 (2008)
• Oracle bought BEA (2008)

WebLogic Server 10 General Features

• Developer productivity ehancements
  • JDK 6, Java EE 5
  • Support of EJB3 and JPA
  • BEA enhancements
• Web Services: more annotations, less XML
  • JAX-RPC Web Services Enhancements
  • JAX-WS 2.0 Web Services Implementation
• Misc:
  • Better administration console
  • Auto-Record of Admin Console actions as WLST scripts
  • Automatic JTA Transaction Recovery Service (TRS) migration
  • SNMP 3.0
  • Production Application Redeployment enhancements
  • Clustering – Unicast messaging (in addition to Multicast)

Programmer Perspective

• New persistence engine: TopLink
• OEPE (Oracle Entreprise Pack for Eclipse): sequence of tools and plugins for Eclipse: remote deployment, debugging,  editors for weblogic.xml and weblogic-application.xml, wizards, facets, Weblogic ClientGen, WSDLC and JAXB wizards
• Optimizations for Spring integration and certication
• Web 2.0:
  • Ajax / Dojo client support
  • Http publish / submit engine for collaborative applications:
    • Bayeux protocol
    • data exchange within applications over persistent connections
    • scalability for Dojo clients
• Ad-hoc tools for:
  • Oracle Database
  • Spring
  • JAX-WS webservices

Lightweight WebLogic Server

WebLogic 10 offers a light weight server:

• Install only “core” WebLogic server
• Optionally, startup other services (JDBC, EJB, JMS, etc.)
• FastSwap: modify classes without requiring redeployment.

Architect Perspective

Architects have to consider WebLogic as a complete suite, and not only WebLogic Server:

• Oracle RAC integration: Connectivity to RAC with load balancing, failover, transactions
• Enterprise Messaging with JMS: High performance and reliable JMS messaging engine “built-in”
• ActiveCache with Coherence*Web and EJB/JPA: Coherence Data Grid caching included and integrated
• Operations Automation: Tools for automating management of applications and servers
• Operations Insight: Tools for diagnosing problems in development and production
• Other features
  • Development tools: Choice of tools for developer productivity
  • Web Services: Enterprise Web Services for SOA
  • TopLink: Persist application data to stores with performance and productivity. It works in a way similar to Hibernate L2 cache.
  • Spring: Enable flexible choice of dev frameworks with same WebLogic QOS

Production and Support Perspective

WebLogic 10 provides a tool: JRockit Mission Control

• monitors more than 150 parameters:
• CPU
  • memory
  • leaks
  • latency spikes
  • threads
  • object references
  • JDBC connections
  • JMS
  • pools
  • clusters
  • configuration files
  • etc.
• allows to compare WebLogic domains
• Runtime Analyzer: runtime capture for offline analysis, Garbage Collector analysis, etc.

Coherence – ActiveCache

Coherence is the Data Grid offered by Oracle. It allows to store Java objects in memory, and share them between all instances. From a certain viewpoint, Coherence looks like the GigaSpaces.

Roadmap for Future WebLogic Releases

• Support of Java EE 6 (ratified by the community in last December)
• OSGi deployment
• More native integration for WebLogic Server – Coherence – Oracle Database
• JRockit Flight Recorder for constant record
• Virtualization
• More integration with Maven, Hudson and Cruise Control
• Shared Library: use the same JAR for many applications, rather than packing the same JAR in different EARs.
• On long term:
  • IDE
    • NetBeans to be oriented onto J2ME development
    • JDevelopper to remain Oracle strategic IDE
    • Contributions to Eclipse to go on
  • JRockit and Sun HotSpot JVMs to be merged.

Case

With Mule ESB, I try to integrate an object of type java.util.Date into a column of type datetime in a Sybase DB table.
I get the following error:
[java] java.sql.SQLException: Operand type clash: java.util.Date is incompatible with DATETIME[/java]

Explanation – Fix

The stacktrace is explicit: java.util.Dates are not compatible with Sybase datetime, as Java’s Strings are not compatible with Sybase numeric(10, 3) for instance.
To fix the issue, you have to cast your java.util.Date as java.sql.Date or java.sql.Timestamp. The cast is very easy to perform:
[java]private static java.sql.Timestamp javaDate2SqlTimestamp(java.util.Date javaDate){
final java.sql.Timestamp answer = new java.sql.Timestamp(javaDate.getTime());
return answer;
}[/java]

The method is quite similar for java.sql.Dates cast.

Context

An object is marshallized and sent on TibcoRV 8.1. An instance of Mule ESB 2.2.1 listens to TibcoRV, reads the message, unmarshalls the object and builds an SQL insert query.

The query is very simple:

[sql]insert into myTable(dateColumn, stringColumn) values(…)[/sql]

It is executed in a Jdbc connector declared on Mule configuration file:

[xml] <jdbc:connector name="jdbcConnector" dataSource-ref="mySybaseDB" pollingFrequency="1000">
<jdbc:query key="writeTest"
value="INSERT INTO myTable(dateColumn, stringColumn)
VALUES(#[map-payload:myJavaDate],#[map-payload:myJavaString])"/>
</jdbc:connector>[/xml]

The DB is Sybase. The first column is of type datetime, the second one is varchar. The values are retrieved from a java.util.Date and a java.lang.String.

Case

When the query is run, I get the error:

[java]java.sql.SQLException: Cannot run this command because Java services are not enabled. A user with System Administrator (SA) role must reconfigure the system to enable Java.[/java]

(you may get a com.sybase.jdbc2.jdbc.SybSQLException instead of java.sql.SQLException)

Explanation – Fix

The error is related only to Sybase, and not to TibcoRV and Mule: by default, Sybase cannot manage Java Dates (java.util.Date). You have to start explicitly the Java services. To perform that:

• login with an username owing the rights “sa_role“
• run the SQL query: [sql]sp_configure ‘enable java’, 1[/sql]
• the restart the Sybase server

Now it should work. A similar error may occur with JBoss.

Case

You have to run a standalone Mule 2.2.1 in debug mode. Since Mule is launched in standalone, you have to debug a remote application.

Fix

Nice case

• Edit the %MULE_HOME%/conf/wrapper.conf
• Uncomment the line:

  wrapper.java.additional.<n>=-Xdebug -Xnoagent -Djava.compiler=NONE -Xrunjdwp:transport=dt_socket,server=y,suspend=y,address=5005

• Don’t forget to set the parameter <n>

Boring case

In my case (Windows XP SP2, Java 1.5), the Mule refused to start and freezed:

------------------------------------------------------------------------
The JVM is being launched with a debugger enabled and could possibly be
suspended.  To avoid unwanted shutdowns, timeouts will be disabled,
removing the ability to detect and restart frozen JVMs.
------------------------------------------------------------------------
Launching a JVM...
Listening for transport dt_socket at address: 5005
------------------------------------------------------------------------
Startup: Timed out waiting for a signal from the JVM.
The JVM was launched with debug options so this may be because the JVM
is currently suspended by a debugger.  Any future timeouts during this
JVM invocation will be silently ignored.
------------------------------------------------------------------------

The fix this:

• Download the jar spring-agent here.
• Move it into %MULE_HOME%/lib/user/
• Edit the %MULE_HOME%/conf/wrapper.conf
• add the following block:

wrapper.java.additional.3=-javaagent:%MULE_HOME%\lib\user\spring-agent-2.5.3.jar
wrapper.java.additional.4=-Xdebug
wrapper.java.additional.5=-Xnoagent
wrapper.java.additional.6=-Djava.compiler=NONE
wrapper.java.additional.7=-Xrunjdwp:transport=dt_socket,server=y,suspend=y,address=5005

• (by the way, even though properties #3 and #5 are inconsistent, don’t mind)
• launch the Mule
• In your IDE (Eclipse, NetBeans, IntelliJ IDEA), run debug on localhost:5005

Case

In a JUnit test, I send a message on a TibcoRV, but I get the following error:

TibrvException[error=4,message=Tibrv not initialized]

Fix

In order, proceed as this:

1. check an RVD daemon is running 😉
2. check tibrvj.jar is in your classpath 😉
3. check the instanciation of transport layer new TibrvRvdTransport(service, network, daemon); is done within your public void testXXX(), and not in the setUp().

Context

Mule 2.2.1 ESB config file with a TibcoRV connector, under Windows XP SP2 and Java 5.
The error happened in this context, yet I assume it would occur in any occurence related to XSD / XML schemas.

Error

org.springframework.beans.factory.xml.XmlBeanDefinitionReader: Ignored XML validation warning
org.xml.sax.SAXParseException: SchemaLocation: schemaLocation value = 'http://www.mulesource.org/schema/mule/management/2.2                http://www.mulesource.org/schema/mule/management/2.2/mule-management.xsd                http://www.mulesource.org/schema/mule/core/2.2                http://www.mulesource.org/schema/mule/core/2.2/mule.xsd                http://www.springframework.org/schema/beans                http://www.springframework.org/schema/beans/spring-beans-2.5.xsd                http://www.mulesource.org/schema/mule/core/2.2/mule.xsd                http://www.mulesource.org/schema/mule/vm/2.2                http://www.mulesource.org/schema/mule/vm/2.2/mule-vm.xsd
http://www.mulesource.org/schema/mule/tibcorv/2.2                http://www.mulesource.org/schema/mule/tibcorv/2.2/mule-tibcorv.xsd' must have even number of URI's.

Headers of XML config file:

[xml]<mule xmlns=&amp;quot;http://www.mulesource.org/schema/mule/core/2.2&amp;quot;
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:spring="http://www.springframework.org/schema/beans"
xmlns:management="http://www.mulesource.org/schema/mule/management/2.2"
xmlns:tibcorv="http://www.mulesource.org/schema/mule/tibcorv/2.2
xsi:schemaLocation="http://www.mulesource.org/schema/mule/management/2.2
http://www.mulesource.org/schema/mule/management/2.2/mule-management.xsd
http://www.mulesource.org/schema/mule/core/2.2
http://www.mulesource.org/schema/mule/core/2.2/mule.xsd
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
http://www.mulesource.org/schema/mule/core/2.2/mule.xsd
http://www.mulesource.org/schema/mule/vm/2.2
http://www.mulesource.org/schema/mule/vm/2.2/mule-vm.xsd
http://www.mulesource.org/schema/mule/tibcorv/2.2
http://www.mulesource.org/schema/mule/tibcorv/2.2/mule-tibcorv.xsd">[/xml]

Explanation – Fix

Each time, the attribute xsi:schemaLocation must have an even number of lines: a “public” XSD address and a “non-public” one. For non English-fluent speakers, I remind that a number is even if, and only if, it is a multiple of 2 ; otherwise it is odd.

In our case, one line is redundant. To fix this issue, you have to remove the redundant line, and ensure each line belongs to a consistent pair of lines: for instance:

http://www.mulesource.org/schema/mule/tibcorv/2.2
and
http://www.mulesource.org/schema/mule/tibcorv/2.2/mule-tibcorv.xsd

When I was introduced to TIBCO Rendezvous (also spelled “Tibco Rendez-Vous” or, shorterly, “TiboRV”), I faced a embarrassing issue: the lack of documentation and tutorials on the web.

The purpose of this -short- tutorial is to guide you until you can send and read a “HelloWorld” message passing through Tibco RendezVous

Installation

• Set the variable JAVA_HOME
  Eg, in my case:

  set JAVA_HOME=C:\exe\java\jdk150_10

• Get the file to be installed:
  TIB_rv_8.1.2_win_x86_vc8.zip
• Unzip the content in your local drive
• Launch the installer (.exe)
  • select Custom installation
  • choose the installation folder, eg: C:\exe\tibco
  • keep default options for other requests
• Set the variable TIBRV_HOME
  Eg, in my case:

  set TIBRV_HOME=C:\exe\tibco\tibrv\8.1

Main Runnables

RVD: Daemon

• Launching the daemon on local host on port 8181 (default port: 7580):

  rvd -http 8181

  You should see the following trace:

  C:\exe\tibco\tibrv\8.1\bin>rvd -http 8181
  
  TIB/Rendezvous daemon
  Copyright 1994-2008 by TIBCO Software Inc.
  All rights reserved.
  
  Version 8.1.2 V8 9/26/2008
  2010-01-19 16:37:02 rvd: Command line: rvd -http 8181
  2010-01-19 16:37:02 rvd: Hostname: MYLOCALMACHINE
  2010-01-19 16:37:02 rvd: Hostname IP address: 123.123.123.123
  2010-01-19 16:37:02 rvd: Detected IP interface: 123.123.123.123 (IP00)
  2010-01-19 16:37:02 rvd: Detected IP interface: 127.0.0.1 (loopback)
  2010-01-19 16:37:02 rvd: Unable to find ticket file tibrv.tkt in PATH
  2010-01-19 16:37:02 rvd: Http interface - http://myLocalMachine.myDomain:8181/

tibrvsend: send a message

To send a message on myLocalMachine:7580:

.\tibrvsend.exe -service 7580 -network MYLOCALMACHINE mySubject myMessage

Expected output:

C:\exe\tibco\tibrv\8.1\bin>.\tibrvsend.exe -service 7580 -network MYLOCALMACHINE mySubject myMessage
Publishing: subject=mySubject "myMessage"
2010-01-19 16:52:11 RV: TIB/Rendezvous Error Not Handled by Process:
{ADV_CLASS="WARN" ADV_SOURCE="SYSTEM" ADV_NAME="LICENSE.EXPIRE" ADV_DESC="The license will expire" expiretime=2010-01-19 16:02:11Z host="10.30.226.147"}

tibrvlisten: listen to messages

Abstract

To listed to messages published on MYLOCALMACHINE:7580, related to subject mySubject:

tibrvlisten -service 7580 -network MYLOCALMACHINE mySubject

Use case: HelloWorld

For instance, let’s assume that you launch this command from one frame:

C:\exe\tibco\tibrv\8.1\bin>.\tibrvsend.exe -service 7580 -network localhost mySubject HelloWorld
Publishing: subject=mySubject "HelloWorld"

Here is what appears in the “listening” frame:

2010-01-19 17:01:32 (2010-01-19 16:01:32.990000000Z): subject=mySubject, message={DATA="HelloWorld"}

Notice you can have many instances listening to the same messages.

Other runnables

Launch the daemon manager

• Launch:

  cd %TIBRV_HOME%/RVDM
  ./RVDM.bat -http 8282 .

• You should see following messages, that you can ignore:

  2010-01-19 13:01:48 rvdm: RVDM has activated.
  2010-01-19 13:02:03 RV: TIB/Rendezvous Error Not Handled by Process:
  {ADV_CLASS="WARN" ADV_SOURCE="SYSTEM" ADV_NAME="LICENSE.EXPIRE" ADV_DESC="The license will expire" e
  xpiretime=2010-01-19 12:11:48Z host="123.123.123.123"}

• To check the daemon is on, you can open the address http://localhost:8282 on your favorite browser.

Example sources

Example sources are available in folder %TIBRV_HOME%/src/examples/java

Misc

TIBRV_HOME\bin folder fosters a couple of binaries:

• rvntscfg.exe: Services Configuration Program

Case:

Under Windows / Tomcat 6:

[java]java.lang.SecurityException: Servlet of class org.apache.catalina.servlets.CGIServlet is privileged and cannot be loaded by this web application[/java]

Fix:

In the web.xml file, add the following block:

[xml]
<context-param>
<param-name>privileged</param-name>
<param-value>true</param-value>
</context-param>[/xml]

Case:

We need use JAXB2 packaged version, rather than the version which is provided within WebLogic 9.2.

Fix:

In the weblogic-application.xml, add the following block:

[xml]
<prefer-application-packages>
<package-name>javax.xml.bind.*</package-name>
</prefer-application-packages>
[/xml]

Yeah, I know this must be widely known, yet I needed a short while before successing ;-).
Case: I must mount a Java projet from a Maven2 file, under Eclipse (I am back to my prefered IDE).

Fix:

• Checkout the sources from version control tool
• Open a console window
• Go to the project home
• (possibly: mvn install)
• mvn eclipse:eclipse
• Open Eclipse
• File > New Project > add the name > check "create project from existing tool" > Finish

And it’s over!