Used Encode.forHtml() instead Encode.forHtmlAttribute
<% if ("regenerate".equals(action)) { %>
<p style="font-size: 12px;margin-top:6px;margin-left:20px;">
- <% String message = MessageFormat.format(resourceBundle.getString("application.regenerated"), Encode.forHtmlAttribute(appBean.getOIDCClientId())); %>
+ <% String message = MessageFormat.format(resourceBundle.getString("application.regenerated"), Encode.forHtml(appBean.getOIDCClientId())); %>
<%= message %>
</p>
<% } %>
