Hello Guys,

As Dropbox was not allowing HTTP URL's for callback or redirect URL's (as http was only allowed for localhost).

I added below redirect URI in dropbox App for local machine :

http://localhost:8080/DropboxTest/oauth_callback

Now, We need to move code on live server or production server then dropbox allow only HTTPS URI for redirection as below :

https://192.168.1.43:8443/DropboxTest/oauth_callback

In above URI, I have changed port to 8443 for SSL.

So, We need to enable SSL on given port number(8443) and add connector as below in server.xml in appache tomcat server.

<Connector port="8443" protocol="HTTP/1.1" SSLEnabled="true" maxThreads="150" scheme="https" secure="true" clientAuth="false" sslProtocol="TLS" sslEnabledProtocols="TLSv1.2,TLSv1.1,TLSv1" keystoreFile="/home/bhagwan/Software/ssslkeystore" keystorePass="admin123456"/>

 Here, "ssslkeystore" is needed which is attached along this blog.

Now, add below lines in web.xml of your project

<!-- SSL configuration -->
     <security-constraint>
          <web-resource-collection>
              <web-resource-name>dropbox</web-resource-name>
              <url-pattern>/oauth_callback</url-pattern>
          </web-resource-collection>    
          <user-data-constraint>
              <transport-guarantee>CONFIDENTIAL</transport-guarantee>
          </user-data-constraint>
      </security-constraint>
 <!-- End SSL configuration -->

Restart your server and deploy your project, now everything should work fine.