Returns the RolePermissionResolver to be used on <em>all</em> configured realms, or <code>null</code (the default)
if all realm instances will each configure their own permission resolver.
@return the RolePermissionResolver to be used on <em>all</em> configured realms, or <code>null</code (the default)
if realm instances will each configure their own role permission resolver.
Returns the RolePermissionResolver to be used on <em>all</em> configured realms, or <code>null</code (the default) if all realm instances will each configure their own permission resolver.
@return the RolePermissionResolver to be used on <em>all</em> configured realms, or <code>null</code (the default) if realm instances will each configure their own role permission resolver.