It appears that it's rather easy to open the smartphone and repair its hardware components, unlike the already mentioned Galaxy S5 and the HTC One (M8). The build of the Z2 is almost identical to that of its predecessor, the Sony Xperia Z1. The teardown also reveals that it's very easy to access one of the most important hardware parts, the motherboard. From there on, you can pretty much access any other component.
You can see the complete teardown of the Sony Xperia Z2 in the gallery below.
source: CNMO via GSMArena