Potential race condition in PluginTenantConfigurableConfigurationHandler

[steven-barnes]

This code uses the double-checked lock pattern:

    public C getConfigurable(@Nullable final UUID kbTenantId) {
        if (kbTenantId != null && !this.configuredTenants.contains(kbTenantId)) {
            synchronized(this.configuredTenants) {
                if (!this.configuredTenants.contains(kbTenantId)) {
                    this.configure(kbTenantId);
                    this.configuredTenants.add(kbTenantId);
                }
            }
        }

        return (C)this.pluginTenantConfigurable.get(kbTenantId);
    }

However configuredTenants can potentially be modified by a different thread while contains is called out side the synchronization block. AFAIK, this is not thread safe.