why is it a bad practise to not initialize primitive fields in a class?

Question

Java primitives always have a default value in the memory of O (booleans are false = 0). So why is it considered as a bad practise to not initialize them, if they even have a predefined value because of this mechanic? And in arrays, even with initialization of a new int[8], all the values in it arent really initialized, but that isnt frowned upon...

Answer 1

By explicitly defining a value, it's clear that you intended that value at that point of execution. If not, another reader might interpret it as if you either forgot to initialize this variable or you don't care at that point (and will set it somewhere else later).

In other words, it's some kind of implicit documentation. Generally, it's considered better practice to write verbose code for better readability; i.e. never use abbreviations for methods names, write them out!

Also, if you have to write line comments (//), you can almost always replace them by wrapping the following code into a well-named method. Implicit documentation ftw! :)