I try to checkout a project on Subversion through the SVN+SSH protocol in Jenkins. It prompts for the credentials as follow.

 

Click the enter credentials link you could fill in the authentication details.

 

The private key is generated by puttygen.exe. After clicking ok, i get the following error.

• javax.servlet.ServletException: java.lang.NullPointerException…

This failure is due to the fact that Jenkins only accepts private key in OpenSSH format. To fix the problem, open puttygen.exe and load your private key. Then export it to OpenSSH Key.

 

Upload the key again and the authentication should work.

Done =)

Reference: How To Make Hudson Support Svn+Ssh Access?