Declaring an Array and altering its contents [duplicate]

Answer 1

Because the Java Language Specification says so

An array initializer may be specified in a declaration (§8.3, §9.3, §14.4), or as part of an array creation expression (§15.10), to create an array and provide some initial values.

So you can either use it as you are already doing

int[] testing = {1,2,3};

or as part of an array creation expression

testing = new int[]{1,2,3};