Posts Tagged ‘Oracle’

Case

From an Agile and TDD viewpoint, performing uni tests on DAO is a requirement. Sometimes, instead of using DBUnit datasets “out of the box”, the developper need test on actual data. In the same vein, when a bug appears on production, isolating and reproducing the issue is a smart way to investigate, and, along the way, fix it.
Therefore, how to export actual data from Oracle DB (or even MySQL, Sybase, DB2, etc.) to a DBUnit dataset as a flat XML file?

Here is a Runtime Test I wrote on this subject:

Fix

Spring

Edit the following Spring context file, setting the login, password, etc.
[xml]
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">

<!– don’t forget to write this, otherwise the application will miss the driver class name, and therfore the test will fail–>
<bean id="driverClassForName" class="org.springframework.beans.factory.config.MethodInvokingFactoryBean">
<property name="targetClass" value="java.lang.Class"/>
<property name="targetMethod" value="forName"/>
<property name="arguments">
<list>
<value>oracle.jdbc.driver.OracleDriver</value>
</list>
</property>
</bean>
<bean id="connexion" class="org.springframework.beans.factory.config.MethodInvokingFactoryBean"
depends-on="driverClassForName">
<property name="targetClass" value="java.sql.DriverManager"/>
<property name="targetMethod" value="getConnection"/>
<property name="arguments">
<list>
<value>jdbc:oracle:thin:@host:1234:SCHEMA</value>
<value>myLogin</value>
<value>myPassword</value>
</list>
</property>
</bean>

<bean id="databaseConnection" class="org.dbunit.database.DatabaseConnection">
<constructor-arg ref="connexion"/>
</bean>
<bean id="queryDataSet" class="org.dbunit.database.QueryDataSet">
<constructor-arg ref="databaseConnection"/>
</bean>
</beans>[/xml]

The bean driverClassForName does not look to be used ; anyway, if Class.forName("oracle.jdbc.driver.OracleDriver") is not called, then the test will raise an exception.
To ensure driverClassForName is created before the bean connexion, I added a attribute depends-on="driverClassForName". The other beans will be created after connexion, since Spring will deduce the needed order of creation via the explicit dependency tree.

Java

[java]public class Oracle2DBUnitExtractor extends TestCase {
private QueryDataSet queryDataSet;

@Before
public void setUp() throws Exception {
final ApplicationContext applicationContext;

applicationContext = new ClassPathXmlApplicationContext(
"lalou/jonathan/Oracle2DBUnitExtractor-applicationContext.xml");
assertNotNull(applicationContext);

queryDataSet = (QueryDataSet) applicationContext.getBean("queryDataSet");

}

@Test
public void testExportTablesInFile() throws DataSetException, IOException {
// add all the needed tables ; take care to write them in the right order, so that you don’t happen to fall on dependencies issues, such as ones related to foreign keys

queryDataSet.addTable("MYTABLE");
queryDataSet.addTable("MYOTHERTABLE");
queryDataSet.addTable("YETANOTHERTABLE");

// Destination XML file into which data needs to be extracted
FlatXmlDataSet.write(queryDataSet, new FileOutputStream("myProject/src/test/runtime/lalou/jonathan/output-dataset.xml"));

}
}[/java]

A Short String

I have a table of which one field is a CLOB. Let’s say I have to insert one record with a short text. The following command is allowed:

[sql]INSERT INTO jonathan_table VALUES (1, ‘hello world!’);[/sql]

A Bigger Text

Error ORA-01704

Now, my text is larger, let’s say 5000 characters. When I launch the same query, I get the following error:

[sql]ORA-01704: string literal too long[/sql]

Indeed, Oracle/SQL*Plus have a limit on CLOB inserts: 4000 bytes.

Workaround

To pass through the limit on canonical SQL, you’ll have to use a PL/SQL procedure. The following command will be successful for any text larger than 4000 bytes, but shorter than 32767:

[sql]DECLARE
bigtext1   VARCHAR2 (32767);
BEGIN
bigtext1 := lpad(‘X’, 32000, ‘X’)
INSERT INTO jonathan_table VALUES (1, bigtext1);
END;[/sql]

An Even Bigger Text

Errors ORA-06550 and PLS-00103

You guess it: beyond this limit of 32 KB, an error occurs. So the following script:

[sql]DECLARE
bigtext1 VARCHAR2 (42000);
BEGIN
bigtext1 := lpad(‘X’, 42000, ‘X’)
INSERT INTO jonathan_table
VALUES (1, bigtext1);
END;
[/sql]

raises such an error:

[sql]Error at line 1
ORA-06550: line 5, column 4:
PLS-00103: Encountered the symbol "INSERT" when expecting one of the following:

. ( * % & = – + ; < / > at in is mod remainder not rem
<an exponent (**)> <> or != or ~= >= <= <> and or like like2
like4 likec between || multiset member submultiset
The symbol ";" was substituted for "INSERT" to continue.[/sql]

Fix this issue

I searched a lot to find an easy fix to go beyond the limit of 32KB. My point was that with Java for instance there is no limit of 32KB. In the same way, with TOAD I was able to update the record with many mega bytes of text, via the clipboard. After further search, I learnt that the 32KB barrier was a SQL*Plus limitation on actual strings, but the patterns insert into ... select ... from were not affected.
Here is the idea:

• create a temporary table
• split the text into blocks shorter than 32KB
• insert the blocks into the temporary table
• perform a first insert with a null CLOB
• update the record using a select on the temporary table (yet you can insert the actual value since previous step)

Here is an example:

[sql]DROP TABLE tt_jonathan_table;
CREATE GLOBAL TEMPORARY TABLE tt_jonathan_table
(
ID NUMBER(10),
pdlsuffix CLOB
) ON COMMIT PRESERVE ROWS;

TRUNCATE TABLE tt_jonathan_table;

DECLARE
bigtext1 VARCHAR2 (32767);
bigtext2 VARCHAR2 (32767);
BEGIN
bigtext1 := lpad(‘X’, 32000, ‘X’)
bigtext2 := lpad(‘Y’, 32000, ‘Y’)
INSERT INTO tt_jonathan_table
VALUES (1, bigtext1);

INSERT INTO tt_jonathan_table
VALUES (2, bigtext2);

INSERT INTO jonathan_table
(id, myClobField)
VALUES (jonathan_seq.NEXTVAL, NULL);

UPDATE jonathan_table
SET myClobField = (SELECT CONCAT (rls1.myClobField, rls2.myClobField)
FROM tt_jonathan_table rls1, tt_jonathan_table rls2
WHERE rls1.ID = 1 AND rls2.ID = 2)
WHERE myClobField is null;
END;
/

TRUNCATE TABLE tt_jonathan_table;
[/sql]

Case

I have had to access a BLOB and read its content. By principle, I dislike using binary objects, which do not suit easy tracing and auditing. Anyway, in my case, floats are stored in a BLOB, and I need read them in order to validate my current development.

You have many ways to read the content of the BLOB. I used two: SQL and Java

SQL

Start your TOAD for Oracle ; you can launch queries similar to this:

[sql]SELECT UTL_RAW.cast_to_binary_float
(DBMS_LOB.submyrecord (myrecord.myrecordess,
4,
1 + (myrecordessnameid * 4)
)
) AS myrecordessvalue
FROM mytable myrecord
WHERE myrecordessid = 123456; [/sql]
You can also run a stored procedure, similar to this:
[sql]
DECLARE
blobAsVariable BLOB;
my_vr RAW (4);
blobValue FLOAT;
bytelen NUMBER := 4;
v_index NUMBER := 5;
jonathan RAW (4);
loopLength INT;
BEGIN
SELECT myField
INTO blobAsVariable
FROM myTable
WHERE tableid = (5646546846);

DBMS_LOB.READ (blobAsVariable, bytelen, 1, jonathan);
loopLength := UTL_RAW.cast_to_binary_integer (jonathan);

FOR rec IN 1 .. loopLength
LOOP
DBMS_LOB.READ (blobAsVariable, bytelen, v_index, my_vr);
blobValue := UTL_RAW.cast_to_binary_float (my_vr);
v_index := v_index + 4;
DBMS_OUTPUT.put_line (TO_CHAR (blobValue));
END LOOP;
END;[/sql]

Java

I am still not sure to be DBA expert. Indeed I am convinced I am more fluent in Java than in PL/SQL 😉

Create a Spring configuration file, let’s say BlobRuntimeTest-applicationContext.xml:
[xml]<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:tx="http://www.springframework.org/schema/tx"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">

<!– $Id: BlobRuntimeTest-applicationContext.xml $ –>
<bean id="dataSource" destroy-method="close" class="org.apache.commons.dbcp.BasicDataSource">
<property name="driverClassName" value="oracle.jdbc.driver.OracleDriver"/>
<property name="url" value="jdbc:oracle:thin:@myDBserver:1234:MY_SCHEMA"/>
<property name="username" value="jonathan"/>
<property name="password" value="lalou"/>
<property name="initialSize" value="2"/>
<property name="minIdle" value="2"/>
</bean>

<bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
<property name="dataSource" ref="dataSource"/>
</bean>

</beans>[/xml]

Now create a runtime test:
[java]/**
* User: Jonathan Lalou
* Date: Aug 7, 2011
* Time: 5:22:33 PM
* $Id: BlobRuntimeTest.java $
*/
public class BlobRuntimeTest extends TestCase {
private static final Logger LOGGER = Logger.getLogger(BlobRuntimeTest.class);

private static final String TABLE = "jonathanTable";
private static final String PK_FIELD = "jonathanTablePK";
private static final String BLOB_FIELD = "myBlobField";
private static final int[] PK_VALUES = {123, 456, 789};

private ApplicationContext applicationContext;
private JdbcTemplate jdbcTemplate;

@Before
public void setUp() throws Exception {
applicationContext = new ClassPathXmlApplicationContext(
"lalou/jonathan/the/cownboy/BlobRuntimeTest-applicationContext.xml");
assertNotNull(applicationContext);
jdbcTemplate = (JdbcTemplate) applicationContext.getBean("jdbcTemplate");
assertNotNull(jdbcTemplate);
}

@After
public void tearDown() throws Exception {
}

@Test
public void testGetArray() throws Exception {
for (int pk_value : PK_VALUES) {
final Blob blob;
final byte[] bytes;
final float[] floats;

blob = (Blob) jdbcTemplate.queryForObject("select " + BLOB_FIELD + " from " + TABLE + " where " + PK_FIELD + " = " + pk_value, Blob.class);
assertNotNull(blob);
bytes = blob.getBytes(1, (int) blob.length());
// process your blob: unzip, read, concat, add, etc..
// floats = ….

LOGGER.info("Blob size: " + floats.length);
LOGGER.info(ToStringBuilder.reflectionToString(floats));
}
}
}
[/java]

Case

In a JDBC DAO, I execute a query to retrieve an object. I get this error:

[java]java.sql.SQLException: Wrong data type: NUMBER in statement [CREATE TABLE Jonathan_Table (TableColumn NUMBER][/java]

Stacktrace

[java]java.sql.SQLException: Wrong data type: NUMBER in statement [CREATE TABLE Jonathan_Table (TableColumn NUMBER]
at org.hsqldb.jdbc.Util.throwError(Unknown Source)
at org.hsqldb.jdbc.jdbcPreparedStatement.executeUpdate(Unknown Source)
at com.bnpp.pb.risklayer.services.dao.jdbc.JdbcPrimeRiskServerDaoUnitTest.getDataSet(JdbcPrimeRiskServerDaoUnitTest.java:57)
at org.dbunit.DatabaseTestCase.setUp(DatabaseTestCase.java:154)[/java]

Explanation and fix

My original DB is under Oracle, but my DBUnit tests works on HSQL. Yet, types NUMBER and VARCHAR2 are not available under HSQL, this is why the exception is raised.
To fixe the issue, rewrite your scripts, replacing NUMBER and VARCHAR2 with NUMERIC and VARCHAR.

Case

Trying to install Oracle Agent on a Windows XP SP2 desktop, I get the following error:
[java]ERROR: OUI-10038:You do not have the necessary permissions to write to the inventory at \Oracle\Inventory. Please make sure that you have the appropriate permissions to perform the installation.[/java]

Fix

Edit the registry. For the key HKEY_LOCAL_MACHINE\SOFTWARE\ORACLE\inst_loc, replace the value \Oracle\Inventory with C:\Oracle\Inventory

Case

You have a stored procedure that you would like to update. The script is OK with TOAD, but raises an error when launched via SQL*Plus.

Fix

Add a slash (‘/’) or a dot (‘.’) at the end of file.

Case

Your application is connected to a database. The configuration of the DB connexion is set in a Spring file. You would like the connexion to be set in WebLogic, so that no URL/login/password lays in your source code.

Steps

WebLogic

Create a new data source:

• go the WebLogic console >
  • JDBC >
    • DataSource >
      • New >
        • set the name, JNDI name (eg: database.jndi.name), DB type  (Oracle, Sybase, …) >
          • Next >
            • Select the driver >
              • Next >
                • Select the targeted server(s)

This will

1. create a new file <yourDomain>/config/jdbc/<datasourceName>-XXXX-jdbc.xml.
2. add a <jdbc-system-resource> block in <yourDomain>/config/config.xml

Spring

Replace the block:

[xml]<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource">
<property name="driverClassName" value="${database.driver}" />
<property name="url" value="${database.url}" />
<property name="username" value="${database.username}" />
<property name="password" value="${database.password}" />
</bean>[/xml]

with:

[xml]<jee:jndi-lookup id="dataSource" jndi-name="${database.jndi.name}" />[/xml]

Case:

I have to redeploy many times a day a WAR on a WebLogic 10 server, using Hotspot (Sun JVM) with Java 6. After some cycles deploy/undeploy, Hotspot crashes with the following error:

java.lang.OutOfMemoryError: PermGen space

Complete stacktrace:

[java]2010-08-17 11:26:56,718 ERROR context.ContextLoader – Context initialization failed
java.lang.IllegalStateException: Unable to load Java 1.5 dependent class [org.springframework.beans.factory.annotation.QualifierAnnotationAutowireCandidateResolver]
at org.springframework.beans.factory.support.AutowireUtils.createAutowireCandidateResolver(AutowireUtils.java:125)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.<init>(DefaultListableBeanFactory.java:103)
at org.springframework.context.support.AbstractRefreshableApplicationContext.createBeanFactory(AbstractRefreshableApplicationContext.java:176)
at org.springframework.context.support.AbstractRefreshableApplicationContext.refreshBeanFactory(AbstractRefreshableApplicationContext.java:121)
at org.springframework.context.support.AbstractApplicationContext.obtainFreshBeanFactory(AbstractApplicationContext.java:423)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:353)
at org.springframework.web.context.ContextLoader.createWebApplicationContext(ContextLoader.java:255)
at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:199)
at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:45)
at weblogic.servlet.internal.EventsManager$FireContextListenerAction.run(EventsManager.java:481)
at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:321)
at weblogic.security.service.SecurityManager.runAs(SecurityManager.java:121)
at weblogic.servlet.internal.EventsManager.notifyContextCreatedEvent(EventsManager.java:181)
at weblogic.servlet.internal.WebAppServletContext.preloadResources(WebAppServletContext.java:1863)
at weblogic.servlet.internal.WebAppServletContext.start(WebAppServletContext.java:3126)
at weblogic.servlet.internal.WebAppModule.startContexts(WebAppModule.java:1512)
at weblogic.servlet.internal.WebAppModule.start(WebAppModule.java:486)
at weblogic.application.internal.flow.ModuleStateDriver$3.next(ModuleStateDriver.java:425)
at weblogic.application.utils.StateMachineDriver.nextState(StateMachineDriver.java:41)
at weblogic.application.internal.flow.ModuleStateDriver.start(ModuleStateDriver.java:119)
at weblogic.application.internal.flow.ScopedModuleDriver.start(ScopedModuleDriver.java:200)
at weblogic.application.internal.flow.ModuleListenerInvoker.start(ModuleListenerInvoker.java:247)
at weblogic.application.internal.flow.ModuleStateDriver$3.next(ModuleStateDriver.java:425)
at weblogic.application.utils.StateMachineDriver.nextState(StateMachineDriver.java:41)
at weblogic.application.internal.flow.ModuleStateDriver.start(ModuleStateDriver.java:119)
at weblogic.application.internal.flow.StartModulesFlow.activate(StartModulesFlow.java:27)
at weblogic.application.internal.BaseDeployment$2.next(BaseDeployment.java:1267)
at weblogic.application.utils.StateMachineDriver.nextState(StateMachineDriver.java:41)
at weblogic.application.internal.BaseDeployment.activate(BaseDeployment.java:409)
at weblogic.application.internal.SingleModuleDeployment.activate(SingleModuleDeployment.java:43)
at weblogic.application.internal.DeploymentStateChecker.activate(DeploymentStateChecker.java:161)
at weblogic.deploy.internal.targetserver.AppContainerInvoker.activate(AppContainerInvoker.java:79)
at weblogic.deploy.internal.targetserver.operations.AbstractOperation.activate(AbstractOperation.java:569)
at weblogic.deploy.internal.targetserver.operations.ActivateOperation.activateDeployment(ActivateOperation.java:150)
at weblogic.deploy.internal.targetserver.operations.ActivateOperation.doCommit(ActivateOperation.java:116)
at weblogic.deploy.internal.targetserver.operations.AbstractOperation.commit(AbstractOperation.java:323)
at weblogic.deploy.internal.targetserver.DeploymentManager.handleDeploymentCommit(DeploymentManager.java:844)
at weblogic.deploy.internal.targetserver.DeploymentManager.activateDeploymentList(DeploymentManager.java:1253)
at weblogic.deploy.internal.targetserver.DeploymentManager.handleCommit(DeploymentManager.java:440)
at weblogic.deploy.internal.targetserver.DeploymentServiceDispatcher.commit(DeploymentServiceDispatcher.java:163)
at weblogic.deploy.service.internal.targetserver.DeploymentReceiverCallbackDeliverer.doCommitCallback(DeploymentReceiverCallbackDeliverer.java:195)
at weblogic.deploy.service.internal.targetserver.DeploymentReceiverCallbackDeliverer.access$100(DeploymentReceiverCallbackDeliverer.java:13)
at weblogic.deploy.service.internal.targetserver.DeploymentReceiverCallbackDeliverer$2.run(DeploymentReceiverCallbackDeliverer.java:68)
at weblogic.work.SelfTuningWorkManagerImpl$WorkAdapterImpl.run(SelfTuningWorkManagerImpl.java:528)
at weblogic.work.ExecuteThread.execute(ExecuteThread.java:201)
at weblogic.work.ExecuteThread.run(ExecuteThread.java:173)
Caused by: java.lang.OutOfMemoryError: PermGen space
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClassCond(ClassLoader.java:632)
at java.lang.ClassLoader.defineClass(ClassLoader.java:616)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141)
at weblogic.utils.classloaders.GenericClassLoader.defineClass(GenericClassLoader.java:328)
at weblogic.utils.classloaders.GenericClassLoader.findLocalClass(GenericClassLoader.java:285)
at weblogic.utils.classloaders.GenericClassLoader.findClass(GenericClassLoader.java:253)
at weblogic.utils.classloaders.ChangeAwareClassLoader.findClass(ChangeAwareClassLoader.java:56)
at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
at java.lang.ClassLoader.loadClass(ClassLoader.java:248)
at weblogic.utils.classloaders.GenericClassLoader.loadClass(GenericClassLoader.java:177)
at weblogic.utils.classloaders.ChangeAwareClassLoader.loadClass(ChangeAwareClassLoader.java:37)
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClassCond(ClassLoader.java:632)
at java.lang.ClassLoader.defineClass(ClassLoader.java:616)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141)
at weblogic.utils.classloaders.GenericClassLoader.defineClass(GenericClassLoader.java:328)
at weblogic.utils.classloaders.GenericClassLoader.findLocalClass(GenericClassLoader.java:285)
at weblogic.utils.classloaders.GenericClassLoader.findClass(GenericClassLoader.java:253)
at weblogic.utils.classloaders.ChangeAwareClassLoader.findClass(ChangeAwareClassLoader.java:56)
at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
at java.lang.ClassLoader.loadClass(ClassLoader.java:248)
at weblogic.utils.classloaders.GenericClassLoader.loadClass(GenericClassLoader.java:177)
at weblogic.utils.classloaders.ChangeAwareClassLoader.loadClass(ChangeAwareClassLoader.java:37)
at org.springframework.util.ClassUtils.forName(ClassUtils.java:242)
at org.springframework.beans.factory.support.AutowireUtils.createAutowireCandidateResolver(AutowireUtils.java:120)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.<init>(DefaultListableBeanFactory.java:103)
at org.springframework.context.support.AbstractRefreshableApplicationContext.createBeanFactory(AbstractRefreshableApplicationContext.java:176)
at org.springframework.context.support.AbstractRefreshableApplicationContext.refreshBeanFactory(AbstractRefreshableApplicationContext.java:121)
at org.springframework.context.support.AbstractApplicationContext.obtainFreshBeanFactory(AbstractApplicationContext.java:423)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:353)
at org.springframework.web.context.ContextLoader.createWebApplicationContext(ContextLoader.java:255)
<Aug 17, 2010 11:26:56 AM CEST> <Warning> <HTTP> <BEA-101162> <User defined listener org.springframework.web.context.ContextLoaderListener failed: java.lang.IllegalStateException: Unable to load Java
1.5 dependent class [org.springframework.beans.factory.annotation.QualifierAnnotationAutowireCandidateResolver].
java.lang.IllegalStateException: Unable to load Java 1.5 dependent class [org.springframework.beans.factory.annotation.QualifierAnnotationAutowireCandidateResolver]
at org.springframework.beans.factory.support.AutowireUtils.createAutowireCandidateResolver(AutowireUtils.java:125)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.<init>(DefaultListableBeanFactory.java:103)
at org.springframework.context.support.AbstractRefreshableApplicationContext.createBeanFactory(AbstractRefreshableApplicationContext.java:176)
at org.springframework.context.support.AbstractRefreshableApplicationContext.refreshBeanFactory(AbstractRefreshableApplicationContext.java:121)
at org.springframework.context.support.AbstractApplicationContext.obtainFreshBeanFactory(AbstractApplicationContext.java:423)
Truncated. see log file for complete stacktrace

Caused By: java.lang.OutOfMemoryError: PermGen space
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClassCond(ClassLoader.java:632)
at java.lang.ClassLoader.defineClass(ClassLoader.java:616)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141)
at weblogic.utils.classloaders.GenericClassLoader.defineClass(GenericClassLoader.java:328)
Truncated. see log file for complete stacktrace
>
<Aug 17, 2010 11:26:56 AM CEST> <Error> <Deployer> <BEA-149265> <Failure occurred in the execution of deployment request with ID ‘1282037204562’ for task ‘9’. Error is: ‘weblogic.application.ModuleException: ‘
weblogic.application.ModuleException:
at weblogic.servlet.internal.WebAppModule.startContexts(WebAppModule.java:1514)
at weblogic.servlet.internal.WebAppModule.start(WebAppModule.java:486)
at weblogic.application.internal.flow.ModuleStateDriver$3.next(ModuleStateDriver.java:425)
at weblogic.application.utils.StateMachineDriver.nextState(StateMachineDriver.java:41)
at weblogic.application.internal.flow.ModuleStateDriver.start(ModuleStateDriver.java:119)
Truncated. see log file for complete stacktrace

Caused By: java.lang.OutOfMemoryError: PermGen space
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClassCond(ClassLoader.java:632)
at java.lang.ClassLoader.defineClass(ClassLoader.java:616)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141)
at weblogic.utils.classloaders.GenericClassLoader.defineClass(GenericClassLoader.java:328)
Truncated. see log file for complete stacktrace
>[/java]

A short explanation

The error seems to be linked to the garbage collection. From what I could read on the web, static objects used in CGlib (and/or jars depending on the library, such as the wide spread Hibernate, Spring, etc.) are the source of the crash.

Fix

Switching HotSpot to Oracle/BEA’s JVM, aka JRockit, makes the error (almost) disappear.
Alternatively, if you can’t change the JVM, a workaround consists in upgrading the following parameter on JVM launching:
-XX:MaxPermSize=256m

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:

You need debug information on SQL queries, for an application within BEA WebLogic 9.2. You need p6spy.

P6spy is a jar which play the role of a bridge between your application and your actual JDBC driver (in my case: oracle.jdbc.driver.OracleDriver for Oracle 10g)

Solution:

• Change JDBC Driver in Weblogic Web Console
  • Services > JDBC > Data Sources > (your data source) > Configuration > Connection Pool > Driver Classname  =  com.p6spy.engine.spy.P6SpyDriver
• Copy p6spy-1.3.jar and spy.properties in %WL_HOME%/servers/lib/ext
• Check that spy.properties contains : realdriver=oracle.jdbc.driver.OracleDriver
• In the spy.properties choose the stdoutLogger,  rather than log4jLogger appender
• In the CLASSPATH of startManagedWebLogic.cmd, add the following path:%WL_HOME%/servers/lib/ext/p6spy-1.3.jar;%WL_HOME%/servers/lib/ext