Name: clC74495 Date: 09/08/98


given:

Object[] a = ...
Object[] b = ...

a.equals(b) is today equivalent to
a == b

This is rather useless. I don't need any special
help to do a == b :-)

Javasoft's solution to this problem is to provide
the new Array.equals(a,b), but it does _not_ work
for multidimensional arrays.

Consider the definition of Array.equals(): it
compares if two arrays are equal by executing
a[i].equals(b[i]) for each element i of the
array. This works great for single-dimensional
arrays, but suppose a and b are defined as:

Object[][] a = ...
Object[][] b = ...

a[i] and b[i] are themselves arrays, but
since arrays do not override Object.equals(),
a[i].equals(b[i]) will check identity equality,
not content equality, for a[i] and b[i].

There are more issues here than just testing
for content equality of multidimensional arrays.
For example, the Collection.contains() method
will fail if passed an array, because
Collection.contains() uses equals(). As I
suspect arrays also don't override hashCode(),
their usefulness in any sort of collection seems
limited to the most mundane Vector applications.

I hope Javasoft will consider fixing this
problem, if not for jdk 1.2 for the following
release. Fixing it soon, however, presents
certain advantages; leaving it until after the
jdk 1.2 release would require you to deprecate
a number of functions under the new class
Arrays. IMHO, there is no reason why the class
Arrays need exist, period; why should one not
be able to say:

int x[] = new int[10];
x.fill(0);
x[2] = 2;
x.sort();

But I'll settle for a working equals() :-)

Thanks,

Evan
(Review ID: 37606)
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