Hi Brian,
I read it to say that changes can become permanent at any time (lazy or
aggressive) and
are guaranteed to be permanent only with a flush().
It does indicate for normal termination, the equivalent of flush occurs,
making pending changes permanent.
There is no statement that ensures a change will *not* become permanent
until a specific action.
So, not a bug.
$.02, Roger
On 12/14/2016 6:20 PM, Brian Burkhalter wrote:
The issue [1] does not seem like a bug to me as the behavior appears to be as
expected from the specification but I would like to see whether anyone else
agrees.
Assuming the nodes “userRoot/a” and “userRoot/a/a1” do not already exist, if
the test [2] is run twice in succession, the printed output of the first run is
"a" exists: false
"a1" exists: false
and that of the second run is
"a" exists: true
"a1" exists: false
This appears to be consistent with this statement in the class level
specification of j.u.Preferences [3]:
"Normal termination of the Java Virtual Machine will not result in the loss of
pending updates -- an explicit flush invocation is not required upon termination to
ensure that pending updates are made persistent.”
I verified that the behavior is consistent with this across Linux, OS X, and
Windows.
Any comment would be appreciated.
Thanks,
Brian
[1] https://bugs.openjdk.java.net/browse/JDK-8151955
[2] RemoveNodeTest.java
import java.util.prefs.BackingStoreException;
import java.util.prefs.Preferences;
public class RemoveNodeTest {
public static void main(String[] args) throws BackingStoreException {
Preferences userRoot = Preferences.userRoot();
System.out.printf("\"a\" exists: %s%n", userRoot.nodeExists("a"));
Preferences a = userRoot.node("a");
System.out.printf("\"a1\" exists: %s%n", a.nodeExists("a1"));
Preferences a1 = a.node("a1");
a.flush();
a1.removeNode();
}
}
[3] http://download.java.net/java/jdk9/docs/api/java/util/prefs/Preferences.html
