1) Open the file
..\sqldeveloper\sqldeveloper\bin\sqldeveloper.conf
and add the following line to set jdk path:
SetJavaHome C:\Program Files\Oracle\11g\product\11.1.0\client_1\jdk
If it don’t allow you to save the file, copy whole sqldeveloper folder to a different location where you have write access to modify this file.
2) Run sqldeveloper.exe (from the new place if you moved the folder out from oracle folders) as administrator and enter the jdk path that comes with your oracle installation:
C:\Program Files\Oracle\11g\product\11.1.0\client_1\jdk\bin
FROM:http://superuser.com/questions/379427/sql-developer-error-messages-enter-the-full-pathname-for-java-exe-and-cannot