At one of my customers I use JDeveloper 11g also as a subversion client. It is actually my first experience of the SVN implementation of JDeveloper, because I'm not able to install a tool like TortoiseSVN on this computer.

I'm pretty positive on the svn-client in Jdev. But unfortunately I haven't found any means to change the password in the UI. At this customer my windows-password has to be changed monthly, and the svn-password depends on it.

Jdeveloper stores the subversion connect info in the file

$APPLICATION_DATA\Roaming\JDeveloper\system11.1.1.6.38.61.92\o.jdeveloper.subversion\repositories.xml

(where "system11.1.1.6.38.61.92" depends on the Jdeveloper build).
The file looks like:

<?xml version = '1.0' encoding = 'UTF-8'?>
<svn-repositories xmlns="http://xmlns.oracle.com/jdeveloper/1013/svn/repositories">
   <svn-repository>
      <url>https://svn.customer.nl/svn/odc/odc-cmr/APPLICATION/source/trunk</url>
      <alias>Application Trunk</alias>
      <user-name>makker</user-name>
      <password>PlainOrEncryptedPasword</password>
   </svn-repository>
</svn-repositories>

Remarkable is the version number in the namespace (1013), since it really comes from my Jdev11g install.

When you first create the connection and give in your username/password via the UI, the password will be stored in here encrypted. But you can also give in an unencrypted password. So I entered my new password in plain format. And it works.

I haven't found how I can encrypt the password, what would, of course, be better. If anyone has a tip, then I'm interested.

You can also rename or delete the file,  then JDeveloper will ask for the new server connection.