could not find or load main class [java]

If you got this error "could not find or load main class" trying to execute your freshly compiled java program you have a problem with your classpath variable that doesn't include your current folder.
Solution:

Open the Control Panel -> System -> Advanced System Settings -> Advanced [table] -> environment variables and then "edit" your CLASSPATH adding a dot "." at the end.

PS
You have to re-open your Windows console to make the change active.

From the Oracle documentation
"The default class path is the current directory. Setting the CLASSPATH variable or using the -classpath command-line option overrides that default, so if you want to include the current directory in the search path, you must include "." in the new settings."

Oracle Database 11g R2: installation hangs [on Windows]!

You are on Windows and Your oracle 11g installation freezes/blocks/stops after the requirements page?

Probably there is an easy solution:

log in as administrator. Even if you tried to install the oracle database11g as a user with admin rights, this is not enough! You have to log in as Amistrator, then it works (probably)!

Oracle 11g R2 client install. hangs on step 5 of 7 in VM with Win. 2008 R2

ASCII, UNICODE, UTF-8, UTF-16, ... character set, encoding ecc

Here I found THE resource on the subjects: character set and encoding.
It's a small and effective guide to the mysterious world of character sets, encodings, Unicode, all that stuff.

http://www.joelonsoftware.com/articles/Unicode.html

How to remove Oracle DB 11 and 12 in Windows

http://stackoverflow.com/questions/8450726/how-to-uninstall-completely-remove-oracle-11g-client

http://docs.oracle.com/cd/E16655_01/install.121/e17720/remove_oracle_sw.htm#LADBI7824

• Uninstall all Oracle components using command line uninstaller located at ORACLE_HOME\deinstall\deinstall

• Run regedit.exe and delete the HKEY_LOCAL_MACHINE/SOFTWARE/ORACLE key. This contains registry entires for all Oracle products.
• Delete any references to Oracle services left behind in the following part of the registry: HKEY_LOCAL_MACHINE/SYSTEM/CurrentControlSet/Services/Ora* It should be pretty obvious which ones relate to Oracle.
• Reboot your machine.
• Delete the "C:\Oracle" directory, or whatever directory is your ORACLE_BASE.
• Delete the "C:\Program Files\Oracle" directory.
• Empty the contents of your "C:\temp" directory.
• Empty your recycle bin.

Fundamentals of Mercurial: the version control software

This two are the most important references to Mercurial, the easy to setup version control system

http://hginit.com/index.html
This tutorial will explain you the fundamental ideas. Just pay attention that
hg commit -m "MESSAGGE"-u USERNAME

A lot of resources are available here!
http://mercurial.selenic.com/wiki/Mercurial


This is the workflow, to use when working with other people (from http://hginit.com/index.html)

1. If you haven’t done so in a while, get the latest version that everyone else is working off of:
• hg pull
• hg up
2. Make some changes
3. Commit them (locally)
4. Repeat steps 2-3 until you’ve got some nice code that you’re willing to inflict on everyone else
5. When you’re ready to share:
• hg pull to get everyone else’s changes (if there are any)
• hg merge to merge them into yours
• test! to make sure the merge didn’t screw anything up
• hg commit (the merge)
• hg push