Are you tired of java.lang.OutOfMemoryError: PermGen space? Then this talk is for you! We'll begin with a crash course in the Java memory model in order to understand what the error message means. Then we'll look at different causes of the error and how to avoid them. We may glance at a few interesting mistakes from the Open Source world. Last but not least you'll learn how you can get rid of java.lang.OutOfMemoryError: PermGen space once and for all.
MySQL Performance Tuning: Top 10 Tips intended for PHP, Ruby and Java developers on performance tuning and optimization of MySQL. We will cover the deadly mistakes to be avoided. We will take real life examples of optimizing application many times. Here is the summary of what we intend to cover:
• Selection of Storage Engine
• Schema Optimization
• Server Tuning
• Hardware Selection and Tuning
• Effective uses of Index, when to use and when not to use.
• Partitions
• Speeding up using Stored Procedures
• Implementing prepared statements?
• Deadly Sins to be avoided
• Performance Tuning and Benchmarking Tools
JDK Flight Recorder introduced in OpenJDK 11.
This feature is low overhead of profiling and be able to used on production environment.
High Performance recording engine is embedded to Hotspot VM.
[오픈소스컨설팅]Day #1 MySQL 엔진소개, 튜닝, 백업 및 복구, 업그레이드방법Ji-Woong Choi
MySQL 소개
간략한 소개
version history
MySQL 사용처
제품 군 변화
시장 변화
MySQL 구성
MySQL 클라이언트 / 서버 개념
클라이언트 프로그램
MySQL 설치
MySQL 버전
MySQL 설치
MySQL 환경 설정
환경설정, 변수 설정
MySQL 스토리지 엔진 소개
MySQL tuning 소개 및 방법
데이터 백업/복구 방법
백업
복구
MySQL Upgrade
MySQL Performance Tuning: Top 10 Tips intended for PHP, Ruby and Java developers on performance tuning and optimization of MySQL. We will cover the deadly mistakes to be avoided. We will take real life examples of optimizing application many times. Here is the summary of what we intend to cover:
• Selection of Storage Engine
• Schema Optimization
• Server Tuning
• Hardware Selection and Tuning
• Effective uses of Index, when to use and when not to use.
• Partitions
• Speeding up using Stored Procedures
• Implementing prepared statements?
• Deadly Sins to be avoided
• Performance Tuning and Benchmarking Tools
JDK Flight Recorder introduced in OpenJDK 11.
This feature is low overhead of profiling and be able to used on production environment.
High Performance recording engine is embedded to Hotspot VM.
[오픈소스컨설팅]Day #1 MySQL 엔진소개, 튜닝, 백업 및 복구, 업그레이드방법Ji-Woong Choi
MySQL 소개
간략한 소개
version history
MySQL 사용처
제품 군 변화
시장 변화
MySQL 구성
MySQL 클라이언트 / 서버 개념
클라이언트 프로그램
MySQL 설치
MySQL 버전
MySQL 설치
MySQL 환경 설정
환경설정, 변수 설정
MySQL 스토리지 엔진 소개
MySQL tuning 소개 및 방법
데이터 백업/복구 방법
백업
복구
MySQL Upgrade
About Flexible Indexing
Postgres’ rich variety of data structures and data-type specific indexes can be confusing for newer and experienced Postgres users alike who may be unsure when and how to use them. For example, gin indexing specializes in the rapid lookup of keys with many duplicates — an area where traditional btree indexes perform poorly. This is particularly useful for json and full text searching. GiST allows for efficient indexing of two-dimensional values and range types.
To listen to the recorded presentation with Bruce Momjian, visit Enterprisedb.com > Resources > Webcasts > Ondemand Webcasts.
For product information and subscriptions, please email sales@enterprisedb.com.
Memory Management: What You Need to Know When Moving to Java 8AppDynamics
This presentation will compare and contrast application behavior in Java 7 with Java 8, particularly focusing on memory management and usage. Several code examples are presented to show how to recognize and respond to common pitfalls.
While most bugs reveal their cause within their stack trace, Java’s OutOfMemoryError is less talkative and therefore regarded as being difficult to debug by a majority of developers. With the right techniques and tools, memory leaks in Java programs can however be tackled like any other programming error. This talks discusses how a JVM stores data, categorizes different types of memory leaks that can occur in a Java program and presents techniques for fixing such errors. Furthermore, we will have a closer look at lambda expressions and their considerable potential of introducing memory leaks when they are used incautiously.
About Flexible Indexing
Postgres’ rich variety of data structures and data-type specific indexes can be confusing for newer and experienced Postgres users alike who may be unsure when and how to use them. For example, gin indexing specializes in the rapid lookup of keys with many duplicates — an area where traditional btree indexes perform poorly. This is particularly useful for json and full text searching. GiST allows for efficient indexing of two-dimensional values and range types.
To listen to the recorded presentation with Bruce Momjian, visit Enterprisedb.com > Resources > Webcasts > Ondemand Webcasts.
For product information and subscriptions, please email sales@enterprisedb.com.
Memory Management: What You Need to Know When Moving to Java 8AppDynamics
This presentation will compare and contrast application behavior in Java 7 with Java 8, particularly focusing on memory management and usage. Several code examples are presented to show how to recognize and respond to common pitfalls.
While most bugs reveal their cause within their stack trace, Java’s OutOfMemoryError is less talkative and therefore regarded as being difficult to debug by a majority of developers. With the right techniques and tools, memory leaks in Java programs can however be tackled like any other programming error. This talks discusses how a JVM stores data, categorizes different types of memory leaks that can occur in a Java program and presents techniques for fixing such errors. Furthermore, we will have a closer look at lambda expressions and their considerable potential of introducing memory leaks when they are used incautiously.
mjprof: Monadic approach for JVM profilingHaim Yadid
A traditional Java profiler consists of two components. One collects profile data from the running application and the other is a visualization user interface to query the data. The profiler capabilities are limited by the data collected but also by the provided reports and functionality. This can be limiting when it comes to complex query of data. In this session we will introduce mjprof. It is an open source textual visualization profiler. It is extremely powerful as it enables you to compose a sequence of simple steps (monads) such as filters, transformations, group-by which let you slice and dice the data to pinpoint the problem. Working with mjprof resembles working with UNIX pipes. We will explain how to use this tool and present use cases and success stories, using this profiler in the last months. mjprof is written in Java and can be found on github as part of the AdoptOpenJDK project.
Using git with submodules. Presentation at the Redpill Linpro Utväcklarkväll in Gothenburg.
The presentation is a bash-script. Have a look at http://github.com/phreaknerd/
Coding for Android on steroids with KotlinKai Koenig
Kotlin is a new language for the JVM that aims to be a "better Java". Made in-house by Jetbrains, the company behind IntelliJ IDEA and also Android Studio, it's been in development for more than 5 years. Just a few weeks ago the final version of Kotlin 1.0 saw the light of day.
This talk will start with a brief introduction into Kotlin and its core language features. After this brief foray into concepts like Kotlin's immutable variables, null behaviour and other smarts like the syntactic sugar it provides for dealing with types and properties you'll discover what's in store for Android developers.
Particularly noteworthy are the decrease in annoying Java boilerplate code, fewer of the irritating "Process has stopped unexpectedly" messages and the easily available Kotlin Android Extensions. You will also explore the toolchain and compiler tools Kotlin provides for Android development, the differences to using Kotlin for Java development as well as the integration into Android Studio.
Next Insurance was founded in the beginning of 2016 and first lines of our production code started accumulating in May 2016. In the beginning I have started writing in Java and experimenting with Kotlin, which saw its 1.0 release two months earlier. 6 months later, the development of our backend services has totally shifted to Kotlin. We still keep a few classes in Java just to make sure that the integration remains seamless but the vast majority of our codebase is written in Kotlin. In this talk I will cover the language features and why I think it is awesome, from null safety to smart casts and data classes. We will also look into the future with 1.1 async/await feature and more.
The workshop is based on several Nikita Salnikov-Tarnovski lectures + my own research. The workshop consists of 2 parts. The first part covers:
- different Java GCs, their main features, advantages and disadvantages;
- principles of GC tuning;
- work with GC Viewer as tool for GC analysis;
- first steps tuning demo;
- comparison primary GCs on Java 1.7 and Java 1.8
The second part covers:
- work with Off-Heap: ByteBuffer / Direct ByteBuffer / Unsafe / MapDB;
- examples and comparison of approaches;
The off-heap-demo: https://github.com/moisieienko-valerii/off-heap-demo
A brief explanation on how the JVM loads and execute its code is done here. Register and stack based execution are explained, and different garbage collection algorithms are shown using graphs to make it easy to understand what happens under the hood. This talk uses the Java Virtual Machine as a main example, but most of the concepts extends to any modern virtual machine available today.
In this short talk, Ishow some great ways you can use Jenkins to supercharge both the development AND deployment of your Ruby projects. Finally, I will demonstrate how you can extend the Jenkins CI server (which is written in Java) with nothing Ruby code.
If you aren't getting the most out of your CI tools, or you aren't using a CI tool at all, then this is for you! Implementing a proper CI is a game changer to the way you and your team develop software.
2013年5月6日に横浜Android and モバイルOS プラットフォーム部で発表した資料です。Androidアプリ開発者向けにOutofMemoryErrorの発生原理とメモリ管理について最新事情を加味してまとめました。Androidアプリにおけるメモリ事情は(初期に比べたら)改善していますが、OpenCVなど画像処理の需要、高解像度対応を踏まえると依然として十分とは言いがたいユースケースもあります。そんな中でメモリ資源をうまく使うための指標となれば幸いです。
Java и Linux — особенности эксплуатации / Алексей Рагозин (Дойче Банк)Ontico
HighLoad++ 2017
Зал «Рио-де-Жанейро», 8 ноября, 11:00
Тезисы:
http://www.highload.ru/2017/abstracts/2884.html
Java на Linux встречается повсеместно в информационных системах от больших данных до новомодных serverless архитектур. Как Linux, так и Java имеют свои эксплуатационные нюансы. Понимание этих нюансов важно, чтобы заставить стек Java + Linux работать стабильно и эффективно.
Но на практике "джависты" очень любят мыслить кроссплатформенно и не хотят разбираться с особенностями операционной системы, a "линускоиды" считают JVM чуждым миру Linux процессом, пожирающим всю доступную на сервере память.
А потом появляется Docker, и нюансов становится ещё больше...
Цель доклада - рассказать "джавистам" про Linux и Docker, а "линуксоидам" про JVM.
Introduction to Java program. Hello World.java. Java Virtual Machine Architecture and how it is working. JVM class loader, Run time Memory, and Execution Engine.
Java Class Loader
http://bd.linkedin.com/in/imranhasanhira
https://www.linkedin.com/company/kona-software-lab-ltd-
Regular java programs doesn't need to mess with class loader. But if someone want to make a framework then it may be helpful to get these classloader things clear in mind.
Most java frameworks use their custom classloader to make coding more dynamic. So understanding the the concepts clearly will definitely boost up the confidence, as well as knowledge about Class Loader.
Code examples are available here: https://github.com/ivailo-pashov/jvmmagic
How well do you know what is going inside the JVM? How about its secret backdoors and nasty hacks? Initially they appear as magic tricks but being aware what is going on behind the scenes will save your time when real issues arise.
Oplægget blev holdt ved InfinIT-arrangementet "Temadag: Java for real-time and embedded systems", der blev afholdt hhv. den 12. og 13. september 2013. Læs mere om arrangementet her: http://infinit.dk/dk/arrangementer/tidligere_arrangementer/temadag_java_for_real-time_and_embedded_systems.htm
Spring Data Requery is alternatives of Spring Data JPA
Requery is lightweight ORM for DBMS (MySQL, PostgreSQL, H2, SQLite, Oracle, SQL Server)
Spring Data Requery provide Query By Native Query, Query By Example and Query By Property like Spring Data JPA
Spring Data Requery is better performance than JPA
Accelerate your Kubernetes clusters with Varnish CachingThijs Feryn
A presentation about the usage and availability of Varnish on Kubernetes. This talk explores the capabilities of Varnish caching and shows how to use the Varnish Helm chart to deploy it to Kubernetes.
This presentation was delivered at K8SUG Singapore. See https://feryn.eu/presentations/accelerate-your-kubernetes-clusters-with-varnish-caching-k8sug-singapore-28-2024 for more details.
Software Delivery At the Speed of AI: Inflectra Invests In AI-Powered QualityInflectra
In this insightful webinar, Inflectra explores how artificial intelligence (AI) is transforming software development and testing. Discover how AI-powered tools are revolutionizing every stage of the software development lifecycle (SDLC), from design and prototyping to testing, deployment, and monitoring.
Learn about:
• The Future of Testing: How AI is shifting testing towards verification, analysis, and higher-level skills, while reducing repetitive tasks.
• Test Automation: How AI-powered test case generation, optimization, and self-healing tests are making testing more efficient and effective.
• Visual Testing: Explore the emerging capabilities of AI in visual testing and how it's set to revolutionize UI verification.
• Inflectra's AI Solutions: See demonstrations of Inflectra's cutting-edge AI tools like the ChatGPT plugin and Azure Open AI platform, designed to streamline your testing process.
Whether you're a developer, tester, or QA professional, this webinar will give you valuable insights into how AI is shaping the future of software delivery.
State of ICS and IoT Cyber Threat Landscape Report 2024 previewPrayukth K V
The IoT and OT threat landscape report has been prepared by the Threat Research Team at Sectrio using data from Sectrio, cyber threat intelligence farming facilities spread across over 85 cities around the world. In addition, Sectrio also runs AI-based advanced threat and payload engagement facilities that serve as sinks to attract and engage sophisticated threat actors, and newer malware including new variants and latent threats that are at an earlier stage of development.
The latest edition of the OT/ICS and IoT security Threat Landscape Report 2024 also covers:
State of global ICS asset and network exposure
Sectoral targets and attacks as well as the cost of ransom
Global APT activity, AI usage, actor and tactic profiles, and implications
Rise in volumes of AI-powered cyberattacks
Major cyber events in 2024
Malware and malicious payload trends
Cyberattack types and targets
Vulnerability exploit attempts on CVEs
Attacks on counties – USA
Expansion of bot farms – how, where, and why
In-depth analysis of the cyber threat landscape across North America, South America, Europe, APAC, and the Middle East
Why are attacks on smart factories rising?
Cyber risk predictions
Axis of attacks – Europe
Systemic attacks in the Middle East
Download the full report from here:
https://sectrio.com/resources/ot-threat-landscape-reports/sectrio-releases-ot-ics-and-iot-security-threat-landscape-report-2024/
Smart TV Buyer Insights Survey 2024 by 91mobiles.pdf91mobiles
91mobiles recently conducted a Smart TV Buyer Insights Survey in which we asked over 3,000 respondents about the TV they own, aspects they look at on a new TV, and their TV buying preferences.
DevOps and Testing slides at DASA ConnectKari Kakkonen
My and Rik Marselis slides at 30.5.2024 DASA Connect conference. We discuss about what is testing, then what is agile testing and finally what is Testing in DevOps. Finally we had lovely workshop with the participants trying to find out different ways to think about quality and testing in different parts of the DevOps infinity loop.
Transcript: Selling digital books in 2024: Insights from industry leaders - T...BookNet Canada
The publishing industry has been selling digital audiobooks and ebooks for over a decade and has found its groove. What’s changed? What has stayed the same? Where do we go from here? Join a group of leading sales peers from across the industry for a conversation about the lessons learned since the popularization of digital books, best practices, digital book supply chain management, and more.
Link to video recording: https://bnctechforum.ca/sessions/selling-digital-books-in-2024-insights-from-industry-leaders/
Presented by BookNet Canada on May 28, 2024, with support from the Department of Canadian Heritage.
PHP Frameworks: I want to break free (IPC Berlin 2024)Ralf Eggert
In this presentation, we examine the challenges and limitations of relying too heavily on PHP frameworks in web development. We discuss the history of PHP and its frameworks to understand how this dependence has evolved. The focus will be on providing concrete tips and strategies to reduce reliance on these frameworks, based on real-world examples and practical considerations. The goal is to equip developers with the skills and knowledge to create more flexible and future-proof web applications. We'll explore the importance of maintaining autonomy in a rapidly changing tech landscape and how to make informed decisions in PHP development.
This talk is aimed at encouraging a more independent approach to using PHP frameworks, moving towards a more flexible and future-proof approach to PHP development.
Search and Society: Reimagining Information Access for Radical FuturesBhaskar Mitra
The field of Information retrieval (IR) is currently undergoing a transformative shift, at least partly due to the emerging applications of generative AI to information access. In this talk, we will deliberate on the sociotechnical implications of generative AI for information access. We will argue that there is both a critical necessity and an exciting opportunity for the IR community to re-center our research agendas on societal needs while dismantling the artificial separation between the work on fairness, accountability, transparency, and ethics in IR and the rest of IR research. Instead of adopting a reactionary strategy of trying to mitigate potential social harms from emerging technologies, the community should aim to proactively set the research agenda for the kinds of systems we should build inspired by diverse explicitly stated sociotechnical imaginaries. The sociotechnical imaginaries that underpin the design and development of information access technologies needs to be explicitly articulated, and we need to develop theories of change in context of these diverse perspectives. Our guiding future imaginaries must be informed by other academic fields, such as democratic theory and critical theory, and should be co-developed with social science scholars, legal scholars, civil rights and social justice activists, and artists, among others.
Key Trends Shaping the Future of Infrastructure.pdfCheryl Hung
Keynote at DIGIT West Expo, Glasgow on 29 May 2024.
Cheryl Hung, ochery.com
Sr Director, Infrastructure Ecosystem, Arm.
The key trends across hardware, cloud and open-source; exploring how these areas are likely to mature and develop over the short and long-term, and then considering how organisations can position themselves to adapt and thrive.
UiPath Test Automation using UiPath Test Suite series, part 4DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 4. In this session, we will cover Test Manager overview along with SAP heatmap.
The UiPath Test Manager overview with SAP heatmap webinar offers a concise yet comprehensive exploration of the role of a Test Manager within SAP environments, coupled with the utilization of heatmaps for effective testing strategies.
Participants will gain insights into the responsibilities, challenges, and best practices associated with test management in SAP projects. Additionally, the webinar delves into the significance of heatmaps as a visual aid for identifying testing priorities, areas of risk, and resource allocation within SAP landscapes. Through this session, attendees can expect to enhance their understanding of test management principles while learning practical approaches to optimize testing processes in SAP environments using heatmap visualization techniques
What will you get from this session?
1. Insights into SAP testing best practices
2. Heatmap utilization for testing
3. Optimization of testing processes
4. Demo
Topics covered:
Execution from the test manager
Orchestrator execution result
Defect reporting
SAP heatmap example with demo
Speaker:
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
JMeter webinar - integration with InfluxDB and GrafanaRTTS
Watch this recorded webinar about real-time monitoring of application performance. See how to integrate Apache JMeter, the open-source leader in performance testing, with InfluxDB, the open-source time-series database, and Grafana, the open-source analytics and visualization application.
In this webinar, we will review the benefits of leveraging InfluxDB and Grafana when executing load tests and demonstrate how these tools are used to visualize performance metrics.
Length: 30 minutes
Session Overview
-------------------------------------------
During this webinar, we will cover the following topics while demonstrating the integrations of JMeter, InfluxDB and Grafana:
- What out-of-the-box solutions are available for real-time monitoring JMeter tests?
- What are the benefits of integrating InfluxDB and Grafana into the load testing stack?
- Which features are provided by Grafana?
- Demonstration of InfluxDB and Grafana using a practice web application
To view the webinar recording, go to:
https://www.rttsweb.com/jmeter-integration-webinar
8. Mattias Jiderhamn – java.jiderhamn.se
JVM memory
Per thread
Local variables and
method parameters
Stack
9. Mattias Jiderhamn – java.jiderhamn.se
JVM memory
Heap
Young generation
Old generation /
tenured space
Eden
space
Survivor
space
Object instances
10. Mattias Jiderhamn – java.jiderhamn.se
JVM memory
Permanent Generation
java.lang.Class instances
etc
Named before JEE and
class unloading
Renamed Metaspace in Java 8
Aka Method area
PermGen /
Metaspace
11. Mattias Jiderhamn – java.jiderhamn.se
java.lang.OutOfMemoryError:
PermGen space / Metaspace
= Too many classes are loaded
What?
13. Mattias Jiderhamn – java.jiderhamn.se
Reason for OOME
1. Your application is too large
-XX:MaxPermSize=256M
Java 8: Metaspace auto increase by default
2. java.lang.Class instances could not
be garbage collected after redeploy
java.lang.OutOfMemoryError:
PermGen space / Metaspace
14. Mattias Jiderhamn – java.jiderhamn.se
Reference types
• Strong (i.e. normal) reference
–Never GC:ed if reachable
• Soft reference
–GC:ed before OutOfMemoryError
• Weak reference (WeakHashMap)
–GC:ed when no Strong or Soft refs
• Phantom reference
–… won’t prevent GC
15. Mattias Jiderhamn – java.jiderhamn.se
Example
Foo
WeakHashMap
Map m = new WeakHashMap();
Foo myFoo = new Foo();
m.put(myFoo, ”bar”);
myFoo = null;
21. Mattias Jiderhamn – java.jiderhamn.se
Application Server
• Application Server bugs
• Logging frameworks
– Apache Commons Logging
Unless LogFactory.release()
– Log4j - some configs
Unless LogManager.shutdown()
– java.util.logging custom Level
• Bean Validation API (JSR 303)
• Unified Expression Language (javax.el)
?
22. Mattias Jiderhamn – java.jiderhamn.se
GC roots
• Class loaded by system ClassLoader
– static field in JDK classes (java.* etc)
• Live thread
– Stack – local vars, method params
–java.lang.Thread instance
• Object held as synchronization monitor
• JNI references
• JVM specials…
23. Mattias Jiderhamn – java.jiderhamn.se
System classes
• java.sql.DriverManager
• Bean introspection cache, shutdown hooks,
custom default Authenticator, custom
security Provider, custom MBeans, custom
ThreadGroup, custom property editor, …
• Reference to contextClassLoader of first caller
25. Mattias Jiderhamn – java.jiderhamn.se
DriverManager
Application Server
app.war
mysql-jdbc.jar
JRE
DriverManager
ClassLoader
com.mysql.jdbc.Driver
1) …
… or 2)
DriverManager.deregisterDriver(…)
26. Mattias Jiderhamn – java.jiderhamn.se
Context shutdown
public class MyCleanupListener implements
javax.servlet.ServletContextListener {
...
/** Called when application is undeployed */
public void contextDestroyed(
ServletContextEvent servletContextEvent) {
DriverManager.deregisterDriver(…);
}
}
33. Mattias Jiderhamn – java.jiderhamn.se
ThreadLocal
ThreadLocal JavaDoc:
”Each thread holds an implicit
reference to its copy of a thread-
local variable as long as the thread
is alive and the ThreadLocal
instance is accessible; …”
38. Mattias Jiderhamn – java.jiderhamn.se
ThreadLocal
ThreadLocalMap JavaDoc:
”However, since reference queues
are not used, stale entries are
guaranteed to be removed only
when the table starts running out
of space”
43. Mattias Jiderhamn – java.jiderhamn.se
Leak Prevention Lib
• Application server independent
– Version 2 core module is pure Java SE!
• Covers a lot more than Tomcat
– System class references avoided/cleared
– Threads are stopped
– ThreadLocals are cleared
– Known offenders handled
• Logs warnings
• Apache 2 licensed
– You may modify and redistribute
54. Mattias Jiderhamn – java.jiderhamn.se
Heap dump
Run application server with
-XX:+HeapDumpOnOutOfMemoryError
-XX:HeapDumpPath=/temp
55. Mattias Jiderhamn – java.jiderhamn.se
Links
Join the fight!
java.jiderhamn.se @mjiderhamn
github.com/mjiderhamn
• ClassLoader Leak Prevention Library
• Step by step guide: acquire heap
dump and analyze for leaks using
Eclipse Memory Analyzer (MAT)
• List of known offenders and links to bug reports
• Submit reports and pull requests!
???
Editor's Notes
No serious amount of web development
Tomcat + luck
https://blogs.oracle.com/jonthecollector/entry/presenting_the_permanent_generation
http://docs.oracle.com/javase/6/docs/technotes/guides/management/jconsole.html
http://www.slideshare.net/waterfox1/an-introduction-to-jvm-internals-and-garbage-collection-in-java good picuture at slide 12
”The Java Memory Model allows each thread to keep a local copy of fields.”
Each thread holds an implicit reference to its copy of a thread-local variable as long as the thread is alive and the ThreadLocal instance is accessible; after a thread goes away, all of its copies of thread-local instances are subject to garbage collection (unless other references to these copies exist).
(except Servlet API…)
(to simplify override by inheritance)
Unsafe: get(), set(), remove() leads to inconsistent state
https://issues.apache.org/bugzilla/show_bug.cgi?id=48895
https://issues.apache.org/bugzilla/show_bug.cgi?id=49159
Tried filter first
Tomcat 7 has ”filter”(?)
Fixed in 1.1
Independent of EL implementation
Fixed in SVN, still wrong in 2.2.1-b04