HCR is failing a lot more often than not for me at the moment. It keeps popping up the \"Hot Code Replace Failed\" dialog, over and over and over. I know there is a checkbox
Window / Preferences -> Java / Debug
There are four checkboxes related to Hot Code Replace. Disabling them all should help you.
An update on Paulo Guedes's answer:
Eclipse Version: 2018-09 (4.9.0) has an 'Enable hot code replace' checkbox under the Hot Code Replace section of Preferences->Java->Debug (dont select any of the sub sections under the reveal arrow beside Debug, it is the top level of Debug that you want).