Morphy's notes

Never forget: hostnames

2012-08-06T15:39:00.001+02:00

From wikipedia:

Restrictions on valid host names Hostnames are composed of series of labels concatenated with dots, as are all domain names. For example, "en.wikipedia.org" is a hostname. Each label must be between 1 and 63 characters long,[1] and the entire hostname (including the delimiting dots) has a maximum of 255 characters. The Internet standards (Request for Comments) for protocols mandate that component hostname labels may contain only the ASCII letters 'a' through 'z' (in a case-insensitive manner), the digits '0' through '9', and the hyphen ('-'). The original specification of hostnames in RFC 952, mandated that labels could not start with a digit or with a hyphen, and must not end with a hyphen. However, a subsequent specification (RFC 1123) permitted hostname labels to start with digits. No other symbols, punctuation characters, or white space are permitted. While a hostname may not contain other characters, such as the underscore character (_), other DNS names may contain the underscore.[2] Systems such as DomainKeys and service records use the underscore as a means to assure that their special character is not confused with hostnames. For example, _http._sctp.www.example.com specifies a service pointer for an SCTP capable webserver host (www) in the domain example.com. Note that some applications (e.g. IE) won't work correctly if any part of the hostname will contain an underscore character[3]. One common cause of non-compliance with this specification is that neither Microsoft Windows nor Android smartphones enforce the rule against using an underscore in hostnames. Since some systems will reject invalid hostnames while others will not, the use of invalid hostname characters may cause subtle problems in systems that connect to standards-based services. For example, RFC-compliant mail servers will refuse to deliver mail for MS Windows computers with names containing underscores. The hostname en.wikipedia.org is composed of the DNS labels en (hostname or leaf domain), wikipedia (second-level domain) and org (top-level domain). Labels such as 2600 and 3abc may be used in hostnames, but -hi- and *hi* are invalid. A hostname is considered to be a fully qualified domain name (FQDN) if all the labels up to and including the top-level domain name (TLD) are specified. The hostname en.wikipedia.org terminates with the top-level domain org and is thus fully qualified. Depending on the operating system DNS software implementation, an unqualified hostname such as csail or wikipedia may be automatically combined with default domain names configured into the system, in order to determine the fully qualified domain name. As an example, a student at MIT may be able to send mail to "joe@csail" and have it automatically qualified by the mail system to be sent to joe@csail.mit.edu. General guidelines on choosing good hostnames are outlined in RFC 1178.

Eheheh just jocking with interfaces

2012-03-30T00:30:00.000+02:00

Any other idea about how to expose a component?

ui... rest... ws... ejb...

package net.sixdeex.jpc.services;

import javax.ejb.Local;
import javax.ejb.Remote;
import javax.ejb.Stateless;
import javax.ejb.TransactionAttribute;
import javax.ejb.TransactionAttributeType;
import javax.jws.WebMethod;
import javax.jws.WebParam;
import javax.jws.WebParam.Mode;
import javax.jws.WebResult;
import javax.jws.WebService;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;

import net.sixdeex.jpc.CalculateDescendCommand;
import net.sixdeex.jpc.framework.CalculateCommand;
import net.sixdeex.jpc.framework.OutputData;

@Path("/x737")
@Produces(MediaType.APPLICATION_JSON)
@Stateless
@Local(X737Calculation.class)
@Remote(RemoteX737Calculation.class)
@TransactionAttribute(TransactionAttributeType.SUPPORTS)
@WebService
public class X737CalculationBean implements RemoteX737Calculation {

    @GET
    @Path("/descend/{from}/{to}")
    @Override
    @WebMethod(operationName = "descend")
    public @WebResult(name = "outputData")
    OutputData descend(
            @PathParam("from") @WebParam(name = "fromLevel", mode = Mode.IN) int fromLevel,
            @PathParam("to") @WebParam(name = "toLevel", mode = Mode.IN) int toLevel) {

        final CalculateCommand calculateDescend = new CalculateDescendCommand(
                null, fromLevel, toLevel);

        return calculateDescend.execute();
    }
}

maven wsimport and deploy phase problem when behind a firewall

2012-03-02T19:58:00.002+01:00

I did a client module that perform wsgen to get the WSDL from the server module and then the wsimport to create the client jar.

Everything works up to the install phase but fails in the deploy phase... the behavior is that mvn succed in uploading the jar but fails to upload the pom with the following error:

Failed to deploy artifacts: Could not find artifact ... in ...

To fix the problem it is required to unset the proxy when calling the wsimport goal with

<httpproxy>::</httpproxy>

as shown in the following pom:

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <groupId>my.group</groupId>
        <artifactId>parent</artifactId>
        <version>0.1-SNAPSHOT</version>
    </parent>

    <modelVersion>4.0.0</modelVersion>

    <groupId>my.group.ws</groupId>
    <artifactId>ws-client</artifactId>
    <version>0.1-SNAPSHOT</version>

    <name>WS client</name>
    <packaging>jar</packaging>

    <dependencies>
        <dependency>
            <groupId>my.group.ws</groupId>
            <artifactId>ws-server</artifactId>
            <version>0.1-SNAPSHOT</version>
        </dependency>
        <dependency>
            <groupId>com.sun.xml.ws</groupId>
            <artifactId>jaxws-rt</artifactId>
            <version>2.2.6</version>
            <scope>provided</scope>
        </dependency>
    </dependencies>

    <build>
        <sourceDirectory>${project.build.directory}/generated-sources/wsimport</sourceDirectory>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>2.3.2</version>
                <configuration>
                    <source>1.6</source>
                    <target>1.6</target>
                    <compilerArguments>
                        <endorseddirs>${project.build.directory}/endorsed</endorseddirs>
                    </compilerArguments>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.jvnet.jax-ws-commons</groupId>
                <artifactId>jaxws-maven-plugin</artifactId>
                <version>2.2</version>
                <executions>
                    <execution>
                        <id>wsgen</id>
                        <phase>initialize</phase>
                        <goals>
                            <goal>wsgen</goal>
                        </goals>
                        <configuration>
                            <sei>my.group.ws.sei.SEIClass</sei>
                            <genWsdl>true</genWsdl>
                            <keep>false</keep>
                        </configuration>
                    </execution>
                    <execution>
                        <id>wsimport</id>
                        <goals>
                            <goal>wsimport</goal>
                        </goals>
                        <configuration>
                            <wsdlDirectory>${project.build.directory}/generated-sources/wsdl</wsdlDirectory>
                            <sourceDestDir>${project.build.directory}/generated-sources/wsimport</sourceDestDir>
                            <keep>false</keep>
                            <httpproxy>::</httpproxy>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-jar-plugin</artifactId>
                <version>2.4</version>
                <configuration>
                    <excludes>
                        <exclude>my/group/ws/jaxws/*</exclude>
                    </excludes>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-dependency-plugin</artifactId>
                <version>2.3</version>
                <executions>
                    <execution>
                        <phase>validate</phase>
                        <goals>
                            <goal>copy</goal>
                        </goals>
                        <configuration>
                            <outputDirectory>${project.build.directory}/endorsed</outputDirectory>
                            <silent>true</silent>
                            <artifactItems>
                                <artifactItem>
                                    <groupId>javax.xml.bind</groupId>
                                    <artifactId>jaxb-api</artifactId>
                                    <version>2.2.4</version>
                                    <type>jar</type>
                                </artifactItem>
                                <artifactItem>
                                    <groupId>javax.xml.ws</groupId>
                                    <artifactId>jaxws-api</artifactId>
                                    <version>2.2.8</version>
                                    <type>jar</type>
                                </artifactItem>
                            </artifactItems>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
</project>

Identifying which Java Thread is consuming most CPU

2011-08-23T16:41:00.000+02:00

A nice way to debug cpu usage by threads in a java process

http://code.nomad-labs.com/2010/11/18/identifying-which-java-thread-is-consuming-most-cpu/

openSuse 11.4, broadcom bcm4312 and Tumbleweed

2011-05-08T11:46:00.000+02:00

it works out of the box after adding the the Packman repo and installing

broadcom_wl and broadcom_wl_kmp_desktop

Kindle whispernet connection

2011-05-08T11:41:00.000+02:00

it's possible to fix kindle connection problems to whispernet following the amazon customer service directives:

Visit your Kindle's Settings screen by selecting that option from the Home screen menu. When you're on the Settings screen, type 311 on Kindle's keyboard.

When prompted to switch wireless providers, select "OK" to see a list of providers in your area. Please allow up to two minutes for Kindle to complete a search of available wireless providers.

Select a carrier from the list and wait for Kindle to return to the Setting screen and attempt to connect to Whispernet. If after two minutes you are still unable to connect or your signal strength does not improve, please repeat the steps above and select a different carrier from the list.

it worked on my kindle 2nd generation

blogilo

2011-04-16T22:37:00.001+02:00

Let's check it out....

jmap

2011-03-01T14:55:00.003+01:00

jmap -heap:format=b <THIS IS A PID!!!>

binary output can be analyzed with MAT

eclipse Helios has preconfigured update site for MAT but it is disabled

look in the "available software site" configuration page and enable the site to install the software

html in kindle

2011-01-16T09:41:00.000+01:00

I copied drools documentation on my kindle in this way:

open documentation as single html page and save using firefox (opera doesn't save images)

open the file with a text editor and remove the following

xmlns="" xmlns:d="http://docbook.org/ns/docbook" xmlns:rf="java:org.jboss.highlight.XhtmlRendererFactory"

import the saved page in the calibre's ebook library, fix metadata and convert to mobi

move the ebook in the kindle

konqueror with webkit instead of khtml

2010-12-10T23:15:00.000+01:00

in KDE (4.5) system settings, go to the file association configuration tool, highlight the text/html extension.

in the right side, in the integration tab, be sure that webkit is before kthml and it will be the default engine for konqueror (if conqueror comes first than firefox in the general tab)

Skype 2.1.0.81 audio problem in voice calls

2010-12-10T23:09:00.000+01:00

get a previous working release at http://download.skype.com/linux/skype-2.1.0.47-suse.i586.rpm

see http://morphy76.blogspot.com/2010/06/skype-21081-in-kubuntu-1004.html

Managing e-books

2010-07-03T15:57:00.004+02:00

I've recently bought Kindle from Amazon and i'm very satisfied (despite the lack of Italian e-books).

It uses a proprietary format (AZW) which is a customization of the open standard MOBI (supported). It supports PDFs too but they suck enough and it doesn't support the e-pub format, then a convertion tool is required!

To convert all of my PDFs like Better builds with Maven i've found a great tool called calibre.

It can organize the virtual library, convert documents (keeping track of formats) and share (natively) with Kindle using both the wireless global network and the USB way.

A great tool.

Skype 2.1.0.81 in Kubuntu 10.04

2010-06-29T15:38:00.002+02:00

This skype release doesn't work: input audio is messed up... looking around i've found that the only fix is to downgrade skype to 2.1.0.47

The downgrade fixes the problem

deb packages can be found here:

http://download.skype.com/linux/skype-ubuntu-intrepid_2.1.0.47-1_amd64.deb
http://download.skype.com/linux/skype-debian_2.1.0.47-1_i386.deb

Kubuntu on Dell Studio

2010-06-29T10:20:00.002+02:00

everytime i switch to windows 7 i get the MBR corrupted and need to reinstall GRUB, very boring even if i'm not so used to switch to windows 7.

i tried to ask Dell support but it seems they don't know which software install on their machine, trying to use my double-boot configuration as a shield to avoid questions like "is there any software that write the MBR regardless the MBR configuration?"

anyway removing Dell software like live backup the issue disappears... i've removed every Dell software, so i'm not sure which one was the real bad guy...

Google Chrome, linux 64 and sun java plugin

2010-06-26T08:09:00.007+02:00

as root
  mkdir /opt/google/chrome/plugins
if missing

then
  cd /opt/google/chrome/plugins
  ln -s ${JRE_HOME}/lib/amd64/libnpjp2.so

and finally (as user)
  google-chrome --enable-plugins %U

check using about:plugins url

ah ehm... windows 7 and kubuntu on dell studio

2010-05-09T13:54:00.004+02:00

need to understand why openSuse 11.2 doesn't install on dell studio 17

dell installation uses 3 primary partitions :(
dell software
recovery
windows 7 installation

resizing the windows 7 partition with th o.s. disk resize tool, kubuntu 10.04 can be easyly installed in an extended partition (1 or 2 Gb swap, 10Gb ext4 mounting /, 10Gb xfs mounting /opt and the rest as crypted xfs mounting /home)

grub on /dev/sda

everything works fine while selecting the kubuntu entry on startup, not the same for windows

it starts, it stops, it de-configures grub O_O and no system can be started anymore...
the error is something like

"unable to find module to load" or something similar

funny :)

i need to understand if this behavior is caused by dell software (like livebackup) or windows 7 startup/shutdown process or the installed McAfee antivirus (1 year with Dell, next i'll come back to avg free)... i'll open a ticket to dell about this issue...

anyway the fix is easy and well known

start with a live distro
mount the / partition
do the grub-install with the option --root-directory and the target the device (/dev/sda)
restart and grub is back

sqlplus coluns

2010-03-03T11:38:00.000+01:00

SQL> set linesize 200

and

/ to re-exec latest query

xerces version exception

2010-02-09T17:54:00.001+01:00

stack identified by
java.lang.AbstractMethodError: org.apache.xerces.dom.DeferredAttrImpl.getTextContent()Ljava/lang/String;
fixed by -Djavax.xml.parsers.DocumentBuilderFactory=com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderFactoryImpl system property

useful system tool

2010-01-30T18:21:00.002+01:00

dmidecode

dmidecode is a tool for dumping a computer's DMI (some say SMBIOS) table contents in a human-readable format. This table contains a description of the system's hardware
components, as well as other useful pieces of information such as serial numbers and BIOS revision. Thanks to this table, you can retrieve this information without hav-
ing to probe for the actual hardware. While this is a good point in terms of report speed and safeness, this also makes the presented information possibly unreliable.

The DMI table doesn't only describe what the system is currently made of, it also can report the possible evolutions (such as the fastest supported CPU or the maximal
amount of memory supported).

2ManDVD

2010-01-09T15:05:00.003+01:00

it's required to create a symbolic link in <workspace>/DVD/MEDIAS to every media used by the project before start generating (i.e. every imported VOB file)

avoid spaces in <workspace> and full project path name

and everything works fine

don't forget to have xine, mkisofs and cdrecord

2009-12-28T23:34:00.000+01:00

Let's test gnome-blog

does it work?

install oracle on opensuse 11.2

2009-11-26T12:35:00.002+01:00

1) rpm -Uvh oracle-xe-univ etc etc as root
2) add yr user to the dba group (if you want handle oracle service and listeners*)
3) enable login for oracle user
4) relogin
5) chmod -R g+w /usr/lib/oracle/xe/app/oracle/product/10.2.0/server/network/log as root
6) /etc/init.d/oracle-xe configure

* disable in yast -> system -> runlevel the oracle service and use lsnctl start/stop and sqlplus / as sysdba startup/shutdown from yr user

Reentrant lock release issue

2009-09-24T13:05:00.001+02:00

don't use shared ReentrantLock before jdk versions hs10(b05), 6u4(b03) , 7(b05); otherwise you can get

java.lang.IllegalMonitorStateException

at java.util.concurrent.locks.ReentrantLock$Sync.tryRelease(ReentrantLock.java:125)

at java.util.concurrent.locks.AbstractQueuedSynchronizer.release(AbstractQueuedSynchronizer.java:1137)

on unlock.

oracle operations on sessions, users and tablespaces

2009-09-23T18:30:00.001+02:00

select SID,SERIAL# from v$session where username like 'RICKDEV';

alter system kill session ;

drop user devrick cascade;

create user devrick identified by devrick;

grant all privileges to devrick;

grant dba to devrick;

drop tablespace TBSTI_DRGMGR_SYSTEM_DATA INCLUDING CONTENTS AND DATAFILES CASCADE CONSTRAINTS;

drop tablespace TBSTI_DRGMGR_SYSTEM_INDEX INCLUDING CONTENTS AND DATAFILES CASCADE CONSTRAINTS;

CREATE TABLESPACE TBSTI_DRGMGR_SYSTEM_DATA DATAFILE '/DRGMGR10/TBSTI_DRGMGR_SYSTEM_dataRick.dbf' SIZE 5M AUTOEXTEND ON NEXT 5M MAXSIZE UNLIMITED LOGGING ONLINE PERMANENT DEFAULT NOCOMPRESS EXTENT MANAGEMENT LOCAL SEGMENT SPACE MANAGEMENT AUTO;

CREATE TABLESPACE TBSTI_DRGMGR_SYSTEM_INDEX DATAFILE '/DRGMGR10/TBSTI_DRGMGR_SYSTEM_indexRick.dbf' SIZE 5M AUTOEXTEND ON NEXT 5M MAXSIZE UNLIMITED LOGGING ONLINE PERMANENT DEFAULT NOCOMPRESS EXTENT MANAGEMENT LOCAL SEGMENT SPACE MANAGEMENT AUTO;

ALTER USER devrick QUOTA UNLIMITED ON TBSTI_DRGMGR_SYSTEM_DATA;

ALTER USER devrick QUOTA UNLIMITED ON TBSTI_DRGMGR_SYSTEM_INDEX;

read environment of unrelated process

2009-09-10T15:42:00.002+02:00

find /proc -name "env*"

and then

cat /proc/<pid>/environ