I love drinking bubble tea, especially in Indonesia, China, and in Japan where there are many famous bubble tea sellers, especially Chatime or KOI (there was one when I visited Indonesia).
However, I was surprised when I came to Japan first time years ago that I couldn't find any "bubble tea" or "bubble milk tea", instead I found "Tapioka juice/tea" (I laughed literally at the naming, well..:)). Because what I imagined of a 'Tapioka (in Indonesia it's called "Tepung Tapioka"') is a "tepung pati ubi kayu (starch flour made from the essence of manioc/cassava).
Explanation: A starch made by leaching and drying the root of the cassava plant; the source of tapioca; a staple food in the tropics.
Comparison in Japan: 【台北】モチモチ食感が堪らない”飲むスイーツ”タピオカティーの人気店５選
So, back to the question:
Why is a bubble tea called 'タピオカジュース' or 'タピオカティー 'in Japan?
What was/is the history behind the naming? (I suspect that it may be 和製英語)