There's no "Show Java Debug Console" option in my Lotus Notes client
The Show Java Debug Console menu is considered an Advanced Menu in Notes 8 and higher and if enabled, it is available under the Tools menu. Click on the below image for a bigger display.
If you have Lotus Notes, Lotus Domino Designer® client and Domino Administrator client installed on your workstation, but the Show Java Debug Console menu does not appear in the Tools menu, then you need to enable the Advanced Menus by selecting View (1) -> Advanced Menus (2) in Notes (see below image). After that, the Show Java Debug Console menu will appear under the Tools menu as in the above image.
If you have a Notes-Only installation on your workstation then the Advanced Menus are not available by default. In this case, the following parameter can be supplied in your notes.ini file which will enable access to advanced menu actions: MenusAdvanced=1
In Lotus Notes 6 or 7, the Show Java Debug Console menu is found in File > Tools > Show Java Debug Console.