hg: jdk/sandbox: 8238566: java.security.Provider$Service.supportsParameter() is racy

[chris.hegarty at oracle.com]

Changeset: 24d5c4ed9bf9
Author:    valeriep
Date:      2020-03-12 22:11 +0000
URL:       https://hg.openjdk.java.net/jdk/sandbox/rev/24d5c4ed9bf9

8238566: java.security.Provider$Service.supportsParameter() is racy
Summary: Use double-checked-locking pattern inside the hasKeyAttributes() method
Reviewed-by: xuelei

! src/java.base/share/classes/java/security/Provider.java