11 October 2014

Head First Servlets & JSP

To keep track of my small contributions to book's errata:

Now it is my two cents for Head First Servlets and JSP.

http://www.oreilly.com/catalog/errata.csp?isbn=9780596516680



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17 September 2014

Eclipse: HTTP Proxy Authentication Required

Eclipse Luna 4.4.0 has a bug when using Proxy to contact to Internet:
(upgrade to 4.4.1 --> Luna SR1)

i.e.:
HTTP Proxy Authentication Required: http://download.eclipse.org/modeling/tmf/xtext/updates/composite/releases/compositeContent.xml
HTTP Proxy Authentication Required: http://download.eclipse.org/modeling/tmf/xtext/updates/composite/releases/compositeContent.xml
Proxy Authentication Required

This is a known bug:

https://bugs.eclipse.org/bugs/show_bug.cgi?id=422665
https://www.eclipse.org/forums/index.php/t/783720/

A functional workaround is:
(provided in the first URL)

Scott Lewis CLA 2014-07-08 17:51:00 EDT 
I've created an updated version of the ECF httpclient4 provider that uses Apache
Httpclient 4.1 (used in Kepler) rather than Apache Httpclient 4.2 (used in Luna 
and the apparent source of this regression).

For those that are experiencing this proxy problem, this update may allow you to
 use your proxy, especially if Kepler (Apache 4.1) install/update worked for you.
 If it *does* work in some of your environments, then it would suggest that the problem
 is not with proxy configuration, but rather with Apache httpclient 4.2 deployed as part
 of Luna.  OTOH if this does not fix things for you, then it may very well be a
 configuration issue.

Disclaimer:  Installing this update, and going back to using an older version of
 httpclient4, could break other plugins.  Even if it works in your environment, 
please do not use it in a production environment unless you are quite sure that
 nothing else is broken by it (e.g. Mylyn).  Also, this repo is not signed so please
 do not redistribute it.  If you are not experiencing any problem wrt this bug,
 please do not install it.

People on this bug who install and try this in their proxy environment please report
 back with what happens via a new comment on this bug.   Since I do not have an
 environment to reproduce this apparent httpclient4 version-specific problem, I must 
depend upon people on this bug that do have such an environment for diagnosis.

Instructions for installation:

1) Download this zip:

http://download.eclipse.org/rt/ecf/httpclient4/org.eclipse.ecf.provider.httpclient4_3.9.0.zip

2) Unzip the contents to your local disk

3) Start Eclipse Luna.  

4) Choose Help->Install New Software->Add...

5) Name:  ECF 3.9.0 Httpclient4 Update

6) Select Local... button on right and navigate your local filesystem to where
 you unzipped the contents to in step 2

7) Navigate into the /archive/site.p2 directory and choose OK

8) There should be a single 'Uncategorized' item in the user Install dialog.
 Select this check box (and all sub-items)

9) Choose Next and step through the remaining wizard pages to finish the install

10) Restart Eclipse when prompted

Then please try to install something into Eclipse.  Whether this works for you
 or not, it would be helpful for you to report your experiences here with as
 much detail as possible.

Thanks.
 
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15 September 2014

JDK8 in WinXP

 As we all know JDK8 installer doesn't work in WinXP.
This is the best solution found at stackoverflow.com :

http://stackoverflow.com/questions/20965564/installing-jdk8-on-windows-xp-advapi32-dll-error#tab-top

This happens because Oracle dropped support for Windows XP (which doesn't have RegDeleteKeyExA used by the installer in its ADVAPI32.DLL by the way) as described in http://mail.openjdk.java.net/pipermail/openjfx-dev/2013-July/009005.html. Yet while the official support for XP has ended, the Java binaries are still (as of Java 8u20 EA b05 at least) XP-compatible - only the installer isn't...
Because of that, the solution is actually quite easy:
  1. get 7-zip (or any other quality archiver), unpack the distribution .exe manually, it has one .zip file inside of it (tools.zip), extract it too,
  2. use unpack200 from JDK8 to unpack all .pack files to .jar files (older unpacks won't work properly); JAVA_HOME environment variable should be set to your Java unpack root, e.g. "C:\Program Files\Java\jdk8" - you can specify it implicitly by e.g.
    SET JAVA_HOME=C:\Program Files\Java\jdk8
    • Unpack all files with a single command (in batch file):
      FOR /R %%f IN (*.pack) DO "%JAVA_HOME%\bin\unpack200.exe" -r -v "%%f" "%%~pf%%~nf.jar"
    • Unpack all files with a single command (command line from JRE root):
      FOR /R %f IN (*.pack) DO "bin\unpack200.exe" -r -v "%f" "%~pf%~nf.jar"
    • Unpack by manually locating the files and unpacking them one-by-one:
      %JAVA_HOME%\bin\unpack200 -r packname.pack packname.jar
    where packname is for example rt
  3. point the tool you want to use (e.g. Netbeans) to the %JAVA_HOME% and you're good to go.
Note: you probably shouldn't do this just to use Java 8 in your web browser or for any similar reason (installing JRE 8 comes to mind); security flaws in early updates of major Java version releases are (mind me) legendary, and adding to that no real support for neither XP nor Java 8 on XP only makes matters much worse. Not to mention you usually don't need Java in your browser (see e.g. http://nakedsecurity.sophos.com/2013/01/15/disable-java-browsers-homeland-security/ - the topic is already covered on many pages, just Google it if you require further info). In any case, AFAIK the only thing required to apply this procedure to JRE is to change some of the paths specified above from \bin\ to \lib\ (the file placement in installer directory tree is a bit different) - yet I strongly advise against doing it.

See also: How can I get the latest JRE / JDK as a zip file rather than EXE or MSI installer?, JRE 1.7 returns: java/lang/NoClassDefFoundError: java/lang/Object

----------------

From
https://blogs.oracle.com/henrik/entry/the_future_of_java_on

Q: Can I install JDK 8 on Windows XP? Will it work?
A: The installer does not work on Windows XP. You can unpack it manually and it will likely run fine.


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Project Euler #125

It is interesting how I analyzed this problem --> first attempt was doing an horrible brute force which  would take milliards of years to complete.

Classical problem, where I had to re-design the solution, after getting a couple of "duplicate numbers" (also incorporated to the problem). Simple & Hard. This is the taxonomy of problems I must create.

My performance is a little slow:

Last 10 Problems Solved

1 Problem 12511 Sep 14 (14:56)
2 Problem 10211 Jan 14 (13:58)

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09 September 2014

OC4J: precompiling JSP

JSPs can be precompiled by OC4J tool: ojspc
http://sqltech.cl/doc/oas10gR31/web.1013/b28961/ojspc.htm

Similar to my last post for WLS:

ojspc -verbose -addclasspath D:\web-oc4j-v3\dist\foo.jar;D:\web-oc4j-v3\dist\lib\bar.jar qux.jsp

As, you can see you need to add libraries to "addclasspath" and the jsp file, or wildcard.

Remember to define environment local variables:

i.e.:

set JAVA_HOME=C:\oracle\jdk150_11
set ORACLE_HOME=D:\oracle\oc4j_extended_101340
set PATH=%ORACLE_HOME%\j2ee\home\jsp\bin;%PATH%
set PATH=%JAVA_HOME%\bin;%PATH%

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02 September 2014

WLS: Precompile ear/war EJB/JSP

WLS has a very useful tool to precompile EJBs and JSPs so we can avoid extra overhead at runtime on the container.

It is called APPC, this tool calls underneath to jspc and ejbc to achieve this task.
http://docs.oracle.com/cd/E17904_01/web.1111/e13719/appc_ejbc.htm#EJBPG1088

After calling setDomainEnv.sh (.cmd) we can execute directly: weblogic.appc [files]

Also, we can compile only JSPs files with: weblogic.jspc [files]
http://docs.oracle.com/cd/E17904_01/web.1111/e13712/reference.htm#i57791

It is recommended to use it at development time as well, so we can hit compilation errors before the first request on the web container.

It exists the Ant task as well: wlapcc

Sample:

java weblogic.jspc -forceGeneration -keepgenerated -verboseJspc -d d:\tmp\export\ -classpath .;D:\proj\webapp-wl-v4\web\WEB-INF\classes;D:\proj\webapp-wl-v4\foo.jar;D:\proj\webapp-wl-v4\lib\bar.jar index.jsp




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19 August 2014

Spring in WLS 12.1.3

Support for Spring Framework on WebLogic Server 12.1.3

WebLogic Server 12.1.3 supports the WebLogic Server/Spring integration features described in this document with Spring Framework versions 3.0.x, 3.1.x, and 4.0.x (note that version 3.2.x is not supported).

Other versions of Spring may be used in WebLogic Server applications without using the integration features described in this document, similar to the way other open source technologies may be used in WebLogic Server applications. In such cases, Oracle does not support the WebLogic Server/Spring integration features, but does provide support for WebLogic Server itself, and does provide problem resolution assistance if WebLogic Server is not providing documented capabilities.

http://docs.oracle.com/middleware/1213/wls/SPRNG/intro.htm#BHCDGJFA
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29 July 2014

JVM for VisualVM

When trying to execute VisualVM you may get:




Cannot find Java 1.7 or higher.
(for 1.3.8)
or

Cannot find Java 1.6 or higher.
 (for 1.3.4)

VisualVM only takes parameters form JVM through arguments or values given at:

visualvm_138/etc/visualvm.conf
(/Applications/VisualVM.app/Contents/Resources/visualvm/etc)

 # Default location of JDK:
#
# It can be overridden on command line by using --jdkhome


# Be careful when changing jdkhome.
# There are two VisualVM launchers for Windows (32-bit and 64-bit) and
# installer points to one of those in the VisualVM application shortcut
# based on the Java version selected at installation time.
#
#visualvm_jdkhome="/path/to/jdk"

Modify :

visualvm_jdkhome="/path/to/jdk"

to your JDK path.

i.e.:

visualvm_jdkhome=C:\oracle\jdk1.7.0_45

visualvm_jdkhome=/Library/Java/JavaVirtualMachines/jdk1.8.0_131.jdk/Contents/Home


This is the same for Netbeans 8.0.1 Portable, but the variable is called: netbeans_jdkhome

- log can be retrieve by:
visualvm -J-Djava.util.logging.config.file=${path_to_jdk_logging_config_file} 

or in the credits (about), there is a bottom to show the standard output (and path to it).
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02 July 2014

WLS Server timeout: ServerLifeCycleTimeoutVal

I wasn't able to start correctly my Admin Server, and the following BEA message appeared in the log:
<BEA-000378> <Server failed to shutdown within the configured timeout of 30 seconds. The server process will exit now.>
 This is for MBean attribute: ServerLifeCycleTimeoutVal

That can be set as System Property at java startup  command line:

        -Dweblogic.ServerLifeCycleTimeoutVal=XXX

where XXX are seconds for timeout.

This can be also configured thru Admin Console at:
(increasing the Server LifeCycle Timeout before executing the force shutdown)

   Domain -> Environment -> Servers -> YOUR_SERVER -> Control --> Start/Stop



More details at:

http://docs.oracle.com/cd/E21764_01/apirefs.1111/e14397/T3Srvr.html
http://docs.oracle.com/cd/E21764_01/web.1111/e13708/server_life.htm
http://docs.oracle.com/cd/E17904_01/apirefs.1111/e13951/core/index.html
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21 June 2014

"Blooper" Contest

A old contest I solved on 2009 from Kadon !

The prize:


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