A default value of 0 for arrays of integral types is guaranteed by the language spec:
Each class variable, instance variable, or array component is initialized with a default value when it is created (§15.9, §15.10) […] For type
int, the default value is zero, that is,0.
If you want to initialize an one-dimensional array to a different value, you can use java.util.Arrays.fill() (which will of course use a loop internally).