Java arrays

An array is simply a sequence of either objects or primitives, all the same type and packaged together under one identifier name. Arrays are defined and used with the square-brackets indexing operator [ ]. To define an array you simply follow your type name with empty square brackets:

int[] a1;

You can also put the square brackets after the identifier to produce exactly the same meaning:

int a1[];

This conforms to expectations from C and C++ programmers. The former style, however, is probably a more sensible syntax, since it says that the type is “ an int array.”

The compiler doesn’t allow you to tell it how big the array is. This brings us back to that issue of “ handles.” All that you have at this point is a handle to an array, and there’s been no space allocated for the array. To create storage for the array you must write an initialization expression. For arrays, initialization can appear anywhere in your code, but you can also use a special kind of initialization expression that must occur at the point where the array is created. This special initialization is a set of values surrounded by curly braces. The storage allocation (the equivalent of using new) is taken care of by the compiler in this case.For example:

int[] a1 = { 1, 2, 3, 4, 5 };