Unzip JHeadstart10. 1 . 2 . 0 .x.zip (using folder names) to a folder of your choice,  for  example C:\JHeadstart (in the next steps referred to as <JHeadstartHome>). 
Find out in which folder JDeveloper  10 . 1 . 2  is installed (in the next steps referred to as <JDeveloperHome>). 
In <JHeadstartHome>\config\jdevaddins you will find a number of JAR files, which need to be installed as plug-ins  for  JDeveloper. Create a  new  directory <JDeveloper_Home>\jdev\lib\ext\jheadstart and copy the JAR files to that directory: You have now extended the JDeveloper 10g IDE with JHeadstart-specific functionality! 
 If  you want to be able to use JHeadstart Designer Generator: in <JHeadstartHome>\config\jdevaddins you will also find a file named migration.xml.  This  file must be copied to the system directory of JDeveloper,  for  example: <JDeveloperHome>\jdev\system10. 1 . 2 . 0 . 0 . 1811 . On Linux  this  directory is in the home directory of the user that is running JDeveloper: $HOME/jdevhome/system10. 1 . 2 . 0 . 0 . 1811 . The exact name of  this  directory depends on the build number of JDeveloper. 
As the last step, we have to tell the plug-ins where the JHeadstart Home is. Start JDeveloper  10 . 1 . 2 , go to the menu option Tools - Preferences, select the category "JHeadstart Settings" and enter the JHeadstart Home. It should report a valid JHeadstart Home and show the version and build number