When writiung javadocs, IntelliJ automatically adds a closing tag for html elements. For instance, after typing <lt>, it automaticaly adds </lt>, or after typing <p>, it adds </p>. It can be annoying since simple html elements like those used in javadocs don't really need ending tags.
To disable javadoc automatic closing tags in IntelliJ, simply go to IntelliJ Preferences -> Editor -> Smart Keys, then on the right panel, uncheck Automatically insert closing tag.
Intellij 14 screenshot:
Intellij 15 screenshot:
A related note, JDK 8 has tightened javadoc syntax check, and as a result self-closing elements like <p/>, or <br/> are deemed invalid and will cause failures. See JDK-8020619. However, this checking can be disabled by passing nonstandard option
-Xdoclint:noneto javadoc tool. For official javadoc guidelines, see How to Write Doc Comments for the Javadoc Tool .