After i run LineJoiner, i can see that data has been modified (number of objects has been reduced), but when i open the shapefile i QGIS, the lines are still segmented even though there are no gaps in between. Altough it has joined some lines, but now all that are connected (sharing same vertexes)
I have FME Workbench 2016.1
It's not creating a Path geometry, is it? Like, what does the Feature Information window have to say about that geometry when it's output from the LineJoiner? Shapefile won't support paths and it would be broken up when written I suspect. Make sure the LineJoiner parameter "Preserver Lines as Path Segments" (if it exists in 2016) is set to No.
If you can share a workspace with a handful of features, it would help us greatly to diagnose the issue.