Architecture and Design trends 2019 Q1

http://infoq.link/architecture-trends-2019

Log4j2 name JMX MBeans

To let name through JMX at MBeans, this can be assigned through

        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-web</artifactId>
            <version>${log4j2.version}</version>
            <scope>provided</scope>
        </dependency>
      
and can be customized:

    <context-param>
        <param-name>log4jContextName</param-name>
        <param-value>spring-mvc-simple-32-nombre</param-value>
    </context-param>


https://logging.apache.org/log4j/2.x/manual/webapp.html

It must be web.xml 3.0

WebLogic log4j2 asm

At starting or deploying time the next exception can be thrown with WebLogic Server :

Caused By: java.lang.IllegalArgumentException
        at com.bea.objectweb.asm.ClassReader.(Unknown Source)
        at com.bea.objectweb.asm.ClassReader.(Unknown Source)
        at weblogic.application.utils.annotation.ClassInfoImpl.(ClassInfoImpl.java:41)
        at weblogic.application.utils.annotation.ClassfinderClassInfos.polulateOneClassInfo(ClassfinderClassInfos.java:240)
        at weblogic.application.utils.annotation.ClassfinderClassInfos.populateClassInfos(ClassfinderClassInfos.java:193)
        at weblogic.application.utils.annotation.ClassfinderClassInfos.(ClassfinderClassInfos.java:44)
        at weblogic.servlet.internal.War.initializeClassInfosIfNecessary(War.java:446)
        at weblogic.servlet.internal.War.getAnnotatedClasses(War.java:376)
        at weblogic.servlet.utils.WarUtils.isJsfApplication(WarUtils.java:258)
        at weblogic.servlet.internal.WebAppModule.detectJsfApplication(WebAppModule.java:277)
        at weblogic.servlet.internal.WebAppModule.init(WebAppModule.java:262)
        at weblogic.servlet.internal.WebAppModule.init(WebAppModule.java:682)
        at weblogic.application.internal.flow.ScopedModuleDriver.init(ScopedModuleDriver.java:162)
        at weblogic.application.internal.ExtensibleModuleWrapper.init(ExtensibleModuleWrapper.java:98)
        at weblogic.application.internal.flow.ModuleListenerInvoker.init(ModuleListenerInvoker.java:84)
        at weblogic.application.internal.flow.InitModulesFlow.initModule(InitModulesFlow.java:288)
        at weblogic.application.internal.flow.InitModulesFlow.initModules(InitModulesFlow.java:301)
        at weblogic.application.internal.flow.InitModulesFlow.prepare(InitModulesFlow.java:329)
        at weblogic.application.internal.BaseDeployment$1.next(BaseDeployment.java:706)
        at weblogic.application.utils.StateMachineDriver.nextState(StateMachineDriver.java:42)
        at weblogic.application.internal.BaseDeployment.prepare(BaseDeployment.java:237)
        at weblogic.application.internal.EarDeployment.prepare(EarDeployment.java:61)
        at weblogic.application.internal.DeploymentStateChecker.prepare(DeploymentStateChecker.java:158)
        at weblogic.deploy.internal.targetserver.AppContainerInvoker.prepare(AppContainerInvoker.java:61)
        at weblogic.deploy.internal.targetserver.operations.ActivateOperation.createAndPrepareContainer(ActivateOperation.java:208)
        at weblogic.deploy.internal.targetserver.operations.ActivateOperation.doPrepare(ActivateOperation.java:98)
        at weblogic.deploy.internal.targetserver.operations.AbstractOperation.prepare(AbstractOperation.java:233)
        at weblogic.deploy.internal.targetserver.DeploymentManager.handleDeploymentPrepare(DeploymentManager.java:749)
        at weblogic.deploy.internal.targetserver.DeploymentManager.prepareDeploymentList(DeploymentManager.java:1238)
        at weblogic.deploy.internal.targetserver.DeploymentManager.handlePrepare(DeploymentManager.java:252)
        at weblogic.deploy.internal.targetserver.DeploymentServiceDispatcher.prepare(DeploymentServiceDispatcher.java:172)


This is caused by having .class bytecode bigger than accepted

Tag: ASM_5_0

        // checks the class version
        if (readShort(off + 6) > Opcodes.V1_8) {
            throw new IllegalArgumentException();
        }
  
One workaround is to remove the classes compiled with the newest bytecode (> 1.8 > 52)

more details:

https://issues.apache.org/jira/browse/LOG4J2-2124

http://mail-archives.apache.org/mod_mbox/logging-notifications/201711.mbox/%3CJIRA.13120226.1511356169000.299143.1511356200159@Atlassian.JIRA%3E

https://gitlab.ow2.org/asm

Busy Socket

Common issue when reading from a socket without timeout:

"main" prio=10 tid=0x00007f79a4009800 nid=0x32ec runnable [0x00007f79aa67a000]
   java.lang.Thread.State: RUNNABLE
    at java.net.SocketInputStream.socketRead0(Native Method)
    at java.net.SocketInputStream.read(SocketInputStream.java:153)
    at java.net.SocketInputStream.read(SocketInputStream.java:122)
    at java.io.ObjectInputStream$PeekInputStream.read(ObjectInputStream.java:2664)
    at java.io.ObjectInputStream$PeekInputStream.readFully(ObjectInputStream.java:2680)
    at java.io.ObjectInputStream$BlockDataInputStream.readShort(ObjectInputStream.java:3157)
    at java.io.ObjectInputStream.readStreamHeader(ObjectInputStream.java:865)
    at java.io.ObjectInputStream.(ObjectInputStream.java:362)
    at com.sun.btrace.client.Client.submit(Client.java:402)
    at com.sun.btrace.client.Main.main(Main.java:206)

---

      sock.setSoTimeout(5 * 1000); //milliseconds

Other details on sockets:

• https://devwebcl.blogspot.com/2018/12/most-interesting-socket-options.html
• https://docs.oracle.com/javase/7/docs/api/java/net/Socket.html#connect(java.net.SocketAddress,%20int)

Btrace cheat sheet

Btrace is a not very popular and powerful tool to debug class at runtime.

The plugin must be installed to run it from visualvm:

Second button to execute it:

Copy the script to be executed thru btrace :

See the results:

It can be executed through command line as well:

btrace <pid> <btrace-script>

$ ./btrace -v -p 2020 -d ./dump/ 64834 TracingScript.java 


More info:

1. https://github.com/btraceio/btrace
2. https://dzone.com/articles/btrace-hidden-gem-java
3. https://www.zcfy.cc/original/btrace-wiki-userguide-mdash-project-kenai

After Now Archeology

Although it has passed 4 years from his original thesis about puzzle game design. Jakko has defended a complete document and began a game.

The blog a thesis can be found at :  http://afternowarcheology.blogspot.fi/

The research refers to several important books/games in the field.

OpenGrok

Open source project from Oracle.

It retrieves information from different control version source code and is indexed with Apache Lucene, making a fast solution for searching (and keep updating).

https://github.com/oracle/opengrok/wiki/How-to-setup-OpenGrok
http://demo.opengrok.org/
https://github.com/oracle/opengrok

Most interesting Socket Options

• TCP_NODELAY
• SO_SNDBUF
• SO_RCVBUF
• Don't forget timeout !

      socket = new Socket(host, port);
      sock.setSoTimeout(5 * 1000); //milliseconds

      socket.setTcpNoDelay(true);
      socket.setSendBufferSize(1000);
      socket.setReceiveBufferSize(1000);

https://eklitzke.org/the-caveats-of-tcp-nodelay
http://normanmaurer.me/presentations/2013-jax-networking-on-jvm/#/41

Don't want to Hassle

    There are a few frameworks to rescue....

• Netty
• Vert.x
• Xnio
• Grizzly
• Apache Mina

Bfile++

Quick analysis as an alternative and abstract layer for Oracle BFILE.

- http://www.jcraft.com/jsch/
  JSch library
  https://docs.spring.io/spring-integration/reference/html/sftp.html
  Under the covers, the SFTP Session Factory relies on the JSch library to provide the SFTP capabilities.

- https://commons.apache.org/proper/commons-net/
  FTPFile (Apache Commons Net 3.6 API)

- Commons VFS
  https://commons.apache.org/proper/commons-vfs

- Xodus (JetBrains)
  https://github.com/JetBrains/xodus
  It has three types of database: a key-value storage, an entity-store and a database for files and streams.

- Flexible Storage System (FS2)
  https://github.com/robertjchristian/fs2
  (un solo developer :( esta buena la idea )

Servers:
(out of scope)

- http://www.alluxio.org/ (service)
- https://www.syncany.org/ (tool)


More info:

https://docs.oracle.com/cd/B28359_01/java.111/b31224/oralob.htm#i1059941
https://stackoverflow.com/questions/51503297/managing-oracle-bfiles
http://www.orafaq.com/wiki/BFILE
https://docs.oracle.com/cd/B28359_01/java.111/b31224/oralob.htm#i1059941

Artist Entities for Coding Books

It is not very common to see in programming books writers, musicians, artist as examples in code samples (usually as entities)

Some examples:

- Get Programming with Haskell

 -  Lovecraft

names = [("Ian", "Curtis"), 
         ("Bernard","Sumner"), 
         ("Peter", "Hook"), 
         ("Stephen","Morris")]


- If Hemingway Wrote JavaScript

    - Ernest Hemingway
    - William Shakespeare
    - André Breton
    - Roberto Bolaño
    - Dan Brown

Table of contents:

Fibonacci
1 Ernest Hemingway
2 William Shakespeare
3 André Breton
4 Roberto Bolaño
5 Dan Brown
Factorial
6 Jack Kerouac
7 Jane Austen
8 Samuel Johnson
9 Sir Arthur Conan Doyle
10 James Joyce
Happy Numbers
11 J.D. Salinger
12 Tupac Shakur
13 Virginia Woolf
14 Geoffrey Chaucer
15 Vladimir Nabokov
Prime Numbers
16 Jorge Luis Borges
17 Lewis Carroll
18 Douglas Adams
19 Charles Dickens
20 David Foster Wallace
Say It
21 Sylvia Plath
22 Italo Calvino
23 J.K. Rowling
24 Arundhati Roy
25 Franz Kafka
Poetic Interludes
1 Edgar Allan Poe
2 William Shakespeare
3 Dylan Thomas
4 Walt Whitman