RFR: 8359809: AttributeList, RoleList and UnresolvedRoleList should never accept other types of Object

[Serguei Spitsyn]

On Fri, 20 Jun 2025 18:18:07 GMT, Kevin Walls <kevinw at openjdk.org> wrote:

>> src/java.management/share/classes/javax/management/relation/RoleList.java line 265:
>> 
>>> 263:     @Override
>>> 264:     public boolean add(Object o) {
>>> 265:         checkTypeSafe(o);
>> 
>> Q: Is `null` allowed? The same question applies to the `addAll()` if these methods allow null to be present in the collection.
>
> The intent here is not to change behaviour regarding nulls.
> Nulls have been permitted, and should stay permitted.
> Other object types (that don't cast to Role, in this file) should fail.
> 
> The Role related files are quite unusual to use, so expect they are mostly used only by the JDK.
> MBean code might more commonly manipulate an AttributeList, and we can still permit nulls in case such code relies on nulls being accepted.

My question was because there are checks for `null` in this class:

public void add(Role role)
        throws IllegalArgumentException {

        if (role == null) {
            throw new IllegalArgumentException("Invalid parameter");
        }
        checkTypeSafe(role);
        super.add(role);
    }

It is kind of confusing and not clear where `null` is allowed and where it is not.
Should it be more consistent?

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/25856#discussion_r2159655977