May 2015 - core-libs-dev

Why isn't Object.notify() a synchronized method?
by Ulf Zibis 04 Jun '15

04 Jun '15

Hi all, in the Javadoc of notify(), notifyAll() and wait(...) I read, that this methods should only be used with synchronisation on it's instance. So I'm wondering, why they don't have the synchronized modifier out of the box in Object class. Also I think, the following note should be moved from wait(long,int) to wait(long): /The current thread must own this object's monitor. The thread releases ownership of this monitor and waits until either of the following two conditions has occurred:// / * /Another thread notifies threads waiting on this object's monitor to wake up either through a call to the notify method or the notifyAll method./ * /The timeout period, specified by timeout milliseconds plus nanos nanoseconds arguments, has elapsed. / Cheers, Ulf

7 8

String.contains(CharSequence) calls toString on argument
by Tomasz Kowalczewski 03 Jun '15

03 Jun '15

Hello! Current implementation of String.contains that accepts CharSequence calls toString on it and passes resulting string to indexOf(String). This IMO defeats the purpose of using CharSequences (that is to have a mutable character buffer and not allocate unnecessary objects). Is changing this a desirable development? It seems pretty straightforward to port indexOf(String) to use CharSequence. If all you need is patch then I can work on it (I have signed OCA) just wanted to make sure it is not a futile work. -- Regards, Tomasz Kowalczewski

6 15

RFR: JDK-8079063 ZoneOffsetTransition constructor should ignore nanoseconds
by Peter Levart 03 Jun '15

03 Jun '15

Hi, Now that JDK-8074003 is in, I'd like to discuss how to tackle JDK-8079063. Package-private ZoneOffsetTransition constructor that takes LocalDateTime transition is invoked from the following 4 places: 1 - the public static factory method: /** * Obtains an instance defining a transition between two offsets. * <p> * Applications should normally obtain an instance from {@link ZoneRules}. * This factory is only intended for use when creating {@link ZoneRules}. * * @param transition the transition date-time at the transition, which never * actually occurs, expressed local to the before offset, not null * @param offsetBefore the offset before the transition, not null * @param offsetAfter the offset at and after the transition, not null * @return the transition, not null * @throws IllegalArgumentException if {@code offsetBefore} and {@code offsetAfter} * are equal, or {@code transition.getNano()} returns non-zero value */ public static ZoneOffsetTransition of(LocalDateTime transition, ZoneOffset offsetBefore, ZoneOffset offsetAfter) { ...this one already disallows transition parameters that have transition.getNano() != 0. 2 - Lines 498..500 of ZoneOffsetTransitionRule: LocalDateTime localDT = LocalDateTime.of(date, time); LocalDateTime transition = timeDefinition.createDateTime(localDT, standardOffset, offsetBefore); return new ZoneOffsetTransition(transition, offsetBefore, offsetAfter); ...where 'time' is an instance field of ZoneOffsetTransitionRule. The ZoneOffsetTransitionRule public static factory method has the following definition: /** * Obtains an instance defining the yearly rule to create transitions between two offsets. * <p> * Applications should normally obtain an instance from {@link ZoneRules}. * This factory is only intended for use when creating {@link ZoneRules}. * * @param month the month of the month-day of the first day of the cutover week, not null * @param dayOfMonthIndicator the day of the month-day of the cutover week, positive if the week is that * day or later, negative if the week is that day or earlier, counting from the last day of the month, * from -28 to 31 excluding 0 * @param dayOfWeek the required day-of-week, null if the month-day should not be changed * @param time the cutover time in the 'before' offset, not null * @param timeEndOfDay whether the time is midnight at the end of day * @param timeDefnition how to interpret the cutover * @param standardOffset the standard offset in force at the cutover, not null * @param offsetBefore the offset before the cutover, not null * @param offsetAfter the offset after the cutover, not null * @return the rule, not null * @throws IllegalArgumentException if the day of month indicator is invalid * @throws IllegalArgumentException if the end of day flag is true when the time is not midnight */ public static ZoneOffsetTransitionRule of( Month month, int dayOfMonthIndicator, DayOfWeek dayOfWeek, LocalTime time, boolean timeEndOfDay, TimeDefinition timeDefnition, ZoneOffset standardOffset, ZoneOffset offsetBefore, ZoneOffset offsetAfter) { Objects.requireNonNull(month, "month"); Objects.requireNonNull(time, "time"); Objects.requireNonNull(timeDefnition, "timeDefnition"); Objects.requireNonNull(standardOffset, "standardOffset"); Objects.requireNonNull(offsetBefore, "offsetBefore"); Objects.requireNonNull(offsetAfter, "offsetAfter"); if (dayOfMonthIndicator < -28 || dayOfMonthIndicator > 31 || dayOfMonthIndicator == 0) { throw new IllegalArgumentException("Day of month indicator must be between -28 and 31 inclusive excluding zero"); } if (timeEndOfDay && time.equals(LocalTime.MIDNIGHT) == false) { throw new IllegalArgumentException("Time must be midnight when end of day flag is true"); } return new ZoneOffsetTransitionRule(month, dayOfMonthIndicator, dayOfWeek, time, timeEndOfDay, timeDefnition, standardOffset, offsetBefore, offsetAfter); } ...which allows 'time' parameter (that becomes ZoneOffsetTransitionRule's 'time' field) with no restriction as to whether it can contain nanos != 0 or not. 3, 4 - Lines 668..678 of ZoneRules private getOffsetInfo method: LocalDateTime dtBefore = savingsLocalTransitions[index]; LocalDateTime dtAfter = savingsLocalTransitions[index + 1]; ZoneOffset offsetBefore = wallOffsets[index / 2]; ZoneOffset offsetAfter = wallOffsets[index / 2 + 1]; if (offsetAfter.getTotalSeconds() > offsetBefore.getTotalSeconds()) { // gap return new ZoneOffsetTransition(dtBefore, offsetBefore, offsetAfter); } else { // overlap return new ZoneOffsetTransition(dtAfter, offsetBefore, offsetAfter); } ...where dtBefore/dtAfter "transition" parameters are taken from savingsLocalTransitions[] array that is filled-in in ZoneRules constructors from passed-in ZoneOffsetTransition objects. So here no nanos != 0 can sneak in if ZoneOffsetTransition invariant holds. The only place where nanos can sneak-in therefore seems to be the public ZoneOffsetTransitionRule.of() factory method. The question is whether the spec. could be changed so that ZoneOffsetTransitionRule.of() factory method would add another @throws definition: * @throws IllegalArgumentException if {@code time.getNano()} returns non-zero value This, I think, would be consistent with ZoneOffsetTransition.of() factory method and I believe early enough in the live of the API so that no custom software would be affected: http://cr.openjdk.java.net/~plevart/jdk9-dev/ZoneOffsetTransitionRule.time/… What do you think? Regards, Peter

3 6

RFR [9] 8072839: JAX-B Plugability Layer: using java.util.ServiceLoader
by Miroslav Kos 03 Jun '15

03 Jun '15

Hi everybody, this is review request for: 8072839: JAX-B Plugability Layer: using java.util.ServiceLoader The JAX-B API changed a little bit - proprietary ServiceLoader-like code has been replaced by java.util.ServiceLoader. This change is required by Jigsaw, old configuration way still supported. JBS:https://bugs.openjdk.java.net/browse/JDK-8072839 webrev: http://cr.openjdk.java.net/~mkos/8072839/jaxws.02/index.html CCC: http://ccc.us.oracle.com/8072839 Testing: JAX-WS (standalone) unit tests, no, jtreg tests available now, TCK/JCK tests will require new tests. Thanks Miran

3 6

8058779: Faster implementation of String.replace(CharSequence, CharSequence)
by Ivan Gerasimov 02 Jun '15

02 Jun '15

Hello everybody! I know many people here like it when the performance is getting better. It was suggested to make the literal variant of String.replace() faster. Currently, this method is implemented as a few calls to regexp API, so that the whole implementation takes only two lines of code. I've created two versions of the fix. In the first one, we scan the string and store indices of the found substrings in an array. Then, we allocate the precisely sized char array and fill it it. The case with the empty target has to be handled separately. BUGURL: https://bugs.openjdk.java.net/browse/JDK-8058779 WEBREV: http://cr.openjdk.java.net/~igerasim/8058779/00/webrev/ The second variant is much less verbose, however it's less efficient too. Here the StringJoiner is used as an intermediate storage. WEBREV: http://cr.openjdk.java.net/~igerasim/8058779/01/webrev/ Here are the micro-benchmark results (in a string of ~300 chars do ~15 replacements). 0) Baseline MyBenchmark.test thrpt 40 257'051.948 ± 4537.484 ops/s 1) Heavy-duty +308% MyBenchmark.test thrpt 40 1'049'235.602 ± 15501.803 ops/s 2) StringJoiner +190% MyBenchmark.test thrpt 40 746'000.629 ± 15387.036 ops/s Personally, I like my first variant better, even though it adds almost 300 lines of code. But I'd like to hear what people think of it. Sincerely yours, Ivan

9 48

JEP 254: Compact Strings
by mark.reinhold＠oracle.com 02 Jun '15

02 Jun '15

New JEP Candidate: http://openjdk.java.net/jeps/254 - Mark

5 9

RFR JDK-8081452: Move sun.nio.cs.AbstractCharsetProvider into jdk.charset/sun.nio.cs.ext
by Xueming Shen 30 May '15

30 May '15

Please help review change to move the AbstractCharsetProvider from java.base/sun.nio.cs to jdk.charsets/sun.nio.cs.ext. This is needed for the modules. issue: https://bugs.openjdk.java.net/browse/JDK-8081452 webrev: http://cr.openjdk.java.net/~sherman/8081452 Thanks, -Sherman

4 7

RFR: 8081536 : (process) remove unreliable ScaleTest from process tests
by Roger Riggs 29 May '15

29 May '15

Please review the removal of the java/lang/ProcessHandle/ScaleTest for ProcessHandles. It is not appropriate for regression testing and does not run reliably. It was inadvertently included in the commit. Webrev: http://bussund0416.us.oracle.com/~rriggs/webrev/webrev-scaletest-remove-808… Issue: 8081536 <https://bugs.openjdk.java.net/browse/JDK-8081536>: (process) remove unreliable ScaleTest from process tests Thanks, Roger

2 1

RFR 8081027: Create a common test to check adequacy of initial size of static HashMap/ArrayList fields
by Ivan Gerasimov 29 May '15

29 May '15

Hello! This is in some way continuation of JDK-8080535 (Expected size of Character.UnicodeBlock.map is not optimal). A new utility class OptimalCapacity was added to jdk.testlibrary package. The test NonOptimalMapSize.java that had been added with JDK-8080535, was rewritten with use of this new class. A couple more tests were added, which utilize methods of OptimalCapacity for checking sizes of ArrayList and IdentityHashMap static variables. Optimization of initial sizes of two more variables saves us one reallocation during java start-time and a few more bytes of memory. Would you please help review this fix? BUGURL: https://bugs.openjdk.java.net/browse/JDK-8081027 WEBREV: http://cr.openjdk.java.net/~igerasim/8081027/00/webrev/ Sincerely yours, Ivan

2 4

[8u-dev] Review request : JDK-8081479: Backport JDBC tests from JDK 9 from test/java/sql and test/javax/sql to JDK 8u.
by Maxim Soloviev 29 May '15

29 May '15

Hello, Please review the test bug fix https://bugs.openjdk.java.net/browse/JDK-8081479 Webrev is http://cr.openjdk.java.net/~kshefov/8081479/webrev.00/ It's a backport of JDK9 JDBC tests to JDK8u. Thanks Maxim

2 1