Differences between the two are
[1] J7 has 5.5 screen size and Moto G3 has 5.0
[2] J7 has 406 adreno Graphics pross Unit( GPU) while Moto G3 has adreno 306 GPU
[3] J7 has 1.5 gb RAM while moto has 2gb RAM
[4] J7 has 1.5 GHz, Octa Core, Exynos 7580 Processor while Moto G3 1.4 GHz, Quad Core, Qualcomm MSM8916 Snapdragon 410 Processor.
[5] J7 has FM radio with recording Moto G3 does not have recording
[6] j7 has 3000 mAH, Li-ion Battery and Moto G3 has 2470 mAH
[7] J7 has removable battery and moto G3 has fixed
[8] J7 can take card slot upto 128Gb while Moto Gb card slot can take 32Gb
[9] J7 is slim 7.9mm and Moto G is 11.9mm
[10] J7 has 1 flash Moto G3 has 2 flashes