rspec/rules/S2116/java/rule.adoc

== Why is this an issue?

While ``++hashCode++`` and ``++toString++`` are available on arrays, they are largely useless. ``++hashCode++`` returns the array's "identity hash code", and ``++toString++`` returns nearly the same value. Neither method's output actually reflects the array's contents. Instead, you should pass the array to the relevant static ``++Arrays++`` method.


=== Noncompliant code example

[source,java]
----
public static void main( String[] args )
{
    String argStr = args.toString(); // Noncompliant
    int argHash = args.hashCode(); // Noncompliant
----


=== Compliant solution

[source,java]
----
public static void main( String[] args )
{
    String argStr = Arrays.toString(args);
    int argHash = Arrays.hashCode(args);
----



ifdef::env-github,rspecator-view[]

'''
== Implementation Specification
(visible only on this page)

=== Message

* Use "Arrays.hashCode(array)" instead.
* Use "Arrays.toString(array)" instead.


'''
== Comments And Links
(visible only on this page)

=== on 10 Oct 2014, 15:25:37 Freddy Mallet wrote:
My 2 cents @Ann:

* I would prefer a rule title like "hashCode" and "toString" methods should never be called on array instances
* I would increase the severity to "Critical"


=== on 15 Jul 2016, 14:24:30 Ann Campbell wrote:
https://github.com/google/error-prone/blob/master/docs/bugpattern/ArrayHashCode.md

endif::env-github,rspecator-view[]