...

Simple installation for Windows-64 bit version

1. Visit http://www.oracle.com/technetwork/developer-tools/sql-developer/downloads/index.html and download the 64-bit version of Oracle SQL Developer for 32-bit Windows, since it already contains a copy of the JDK. The 32-bit version of Oracle SQL Developer will run on 64-bit Windows. The 32/64 bit installer will also work, but you should use the 64-bit version specifically since it also includes Java. if you want to use the 32/64-bit installer instead, then you will need to follow the two-part installation process discussed in the next section.
   
   
2. There is no installer for this software. Simply download the ZIP file, extract the zipped-up folder, and launch the SqlDeveloper executable inside that folder. You may move the extracted folder where you want on your hard drive and create a shortcut to it on your desktop or wherever you wish.  
   
   
   
3. The first time you launch Oracle SQL Developer you will also be prompted to associate certain file types with it. You should select all file types and click ok.
   
   
   
   
4. Once it finishes launching, Oracle SQL Developer should look like this. You may begin using it.
   
   

Two part installation for Windows-32bit, Mac and Linux

Download and Install Java SDK

...