How can I change the language (to english) in Oracle SQL Developer?

I am running a non-english Windows 7 system, and apparently Oracle SQL Developer (version 3.0.04.34, 64-bit) tries to auto-guess my preferred language based on the OS. Is there any way to change the language to english?

I've tried the tip found at http://misteratmisis.com/infotech/how-change-oracle-sql-developer-interface-japanese-english, namely adding the VM options

AddVMOption -Duser.language=en
AddVMOption -Duser.country=US

to file ide.conf in directory

/ide/bin

within the SQL Developer installation directory, as suggested, but that didn't help.

Solution (edited on 13.09.2012):

I decided to try again the solution proposed by Alex K. and this time it worked, namely adding

AddVMOption  -Duser.language=en

to the file sqldeveloper.conf file located in sqldeveloper\bin\ folder. I presume that it did work now but not before, because meanwhile I have changed my UAC (user access control) settings in Windows 7 so that I am administrator by default. What happened before was probably that even though the changes appeared to be there, the configuration file read by the program was another one (shadow copy).

Solution for Mac OS X (added on 26.02.2016):

Edit file at

/Applications/SQLDeveloper.app/Contents/Resources/sqldeveloper/sqldeveloper/bin/sqldeveloper.conf

and add the line

AddVMOption  -Duser.language=en

(Tested with SQL Developer 4.1.3.20)

Try to set user.language and user.country properties in sqldeveloper.conf file located in sqldeveloper\bin folder (%APPDATA%\sqldeveloper\<version>\product.conf for more recent versions) .
Sample for set french language:

IncludeConfFile ../../ide/bin/ide.conf

SetJavaHome D:\jdk1.6.0_25

AddVMOption  -Doracle.ide.util.AddinPolicyUtils.OVERRIDE_FLAG=true

AddVMOption -Dsun.java2d.ddoffscreen=false

AddVMOption -Dwindows.shell.font.languages=
AddVMOption -Duser.language=fr
AddVMOption -Duser.country=FR
AddVMOption  -XX:MaxPermSize=128M

AddVMOption -Doracle.jdbc.mapDateToTimestamp=false  
IncludeConfFile  sqldeveloper-nondebug.conf

To switch off language try to remove its support by editing oracle.translated.locales option in ide.boot file (located in ide\bin folder).
For example, if I want to 'break' french language support this option will be:

oracle.translated.locales = de,es,it,ja,ko,pt_BR,zh_CN,zh_TW

The original value was:

oracle.translated.locales = de,fr,es,it,ja,ko,pt_BR,zh_CN,zh_TW

The configuration above (sqldeveloper.conf file) will be wrong after remove french support and the french language does not appear as GUI localization.

You can also set language at runtime

sqldeveloper.exe --AddVMOption=-Duser.language=en

to avoid editing sqldeveloper.conf every time you install new version.

You can also configure directly on the file ..sqldeveloper\ide\bin\ide.conf:

Just add the JVM Option: > AddVMOption -Duser.language=en

The file will be like this:

Or use the menu: Tools->Preferences->Database->NLS and change language and territory.

With SQL Developer 4.x, the language option is to be added to ..\sqldeveloper\bin\sqldeveloper.conf, rather than ..\sqldeveloper\bin\ide.conf:

# ----- MODIFICATION BEGIN -----
AddVMOption -Duser.language=en
# ----- MODIFICATION END -----

Before installation use the Control Panel Region and Language Preferences tool to change everything (Format, Keyboard default input, language for non Unicode programs) to English. Revert to the original selections after the installation.

On MAC High Sierra (10.13.6)

cd /Users/vkrishna/.sqldeveloper/18.2.0

nano product.conf

on the last line add

AddVMOption -Duser.language=en

Save the file and restart.

=======================================

If you are using standalone Oracle Data Modeller

find ~/ -name "datamodeler.conf"

and edit this file

cd /Users/vkrishna//Desktop/OracleDataModeler-18.2.0.179.0756.app/Contents/Resources/datamodeler/datamodeler/bin/

Add somewhere in the last

AddVMOption -Duser.language=en

save and restart, done!

+> In Oracle SQL Developer, you can follow steps by steps as the below image:

+> After opening the file in step 3, you can add this text "AddVMOption -Duser.language=en" to this file and save it.

+> After saving the file, reopen Oracle SQL Developer and check the result.