Yes, Samsung Galaxy J Max does have the memory card slot.
Yes, Samsung Galaxy J Max does have the 4G VoLTE support.
Yes, Samsung Galaxy J Max does have the 3.5 headphone jack.
No. Samsung Galaxy J Max does not have the AMOLED display. It has WXGA display.
No. Samsung Galaxy J Max tablet does not have the front camera flash.
The J Max is a very perplexing device. It is built well and is amongst the better looking Samsung budget handsets. The battery life is stellar and the display is great for content consumption.
It’s hard to recommend this phone when anything between just a few hundred to a thousand odd rupees extra can get you phones with significantly better screen, larger battery, powerful hardware, competent camera, and latest version of Android.