Note that the build will take much more time in a dynamic view (network access) than in a snapshot one (local disk access).
See "What are the differences between a snapshot view and a dynamic view?".
Before disabling the "Build automatically" eclipse option, check if the issue persists in a snapshot view.
Anyway, an automatic build is generally active only in a continuous integration environment (as shown in this article).
The OP reports the following solution:
Disable the build-before-launch:
- Select "
Window->Preferences
".- In the tree view pane, expand the "
Run/Debug
" node, and select "Launching
".- Disable (uncheck) the "
Build (if required) before launching
" option in the "General Options
" section, and then click "OK".
The Launching Preferences for Juno do mention that this option is "on" by default.