Maven

This is an early release for 3.0.0 to allow preparations for the breaking API changes and cleanups.

Please check out the wiki page What's different in 3.0 from time to time for the details and migration guide.

API changes

• Rename onErrorResumeNext(<source>) to onErrorResumeWith(<source>) to avoid lambda ambiguity with onErrorResumeNext(Function). (#6550)
• Remove buffer(Supplier) variants (#6564)
• Remove window(Supplier) variants (#6564)
• Remove onExceptionResumeNext (#6564)

Behavior changes

No behavior changes in this release.

Bugfixes

• Fix NPE when debouncing empty source (#6559)

Documentation enhancements

• Fix wording in Single javadocs (#6566)

Other

• Fixing version tag since Schedulers.from(Executor, boolean) has been promoted. (#6544)
• Simplify JUnit tests with more appropriate assert methods (#6549)
• Remove unnecessary static imports from unit tests (#6550)

Maven

This is an early release for 3.0.0 to verify the release process still works for the new artifact location.

This release note does not detail the changes since 2.2.x. Please check out the wiki page What's different in 3.0 from time to time for the details and migration guide.

API changes

• Add eager truncation to bounded replay() to avoid item retention (#6532)
• Add X.fromSupplier() (#6529)
• Add concatMap with Scheduler guaranteeing where the mapper function runs (#6538)
• Add startWithItem & startWithIterable (#6530)
• ConnectableFlowable/ConnetableFlowable redesign (#6519)
• Merge as() into to() (#6514)
• Change Maybe.defaultIfEmpty() to return Single (#6517)
• Widen functional interface throws, replace Callable with Supplier in operator signatures (#6511)
• Promote Beta/Experimental operators to Standard (#6537)
• Remove getValues() from some subjects/processors (#6516)
• Remove methods from test consumers, make internal versions (#6526)
• Remove replay(Scheduler) and its overloads (#6539)
• Remove dematerialize() (#6539)
• Remove startWith(T|Iterable) (#6530)
• Remove as() (#6514)
• Remove Maybe.toSingle(T) (#6517)
• Remove Flowable.subscribe(4 args) (#6517)
• Remove Observable.subscribe(4 args) (#6517)
• Remove Single.toCompletable() (#6517)
• Remove Completable.blockingGet() (#6517)

Behavior changes

• Make using() resource disposal order consistent with eager-mode (#6534)
• ConnectableFlowable/ConnetableFlowable redesign (#6519)
• Add eager truncation to bounded replay() to avoid item retention (#6532)

Bugfixes

• Fix concatMapDelayError not continuing on fused inner source crash (#6523)
• Sync up with 2.2.10 snapshot (#6507)
• Merge in changes from 2.x since the initial branching (#6498)

Documentation enhancements

• Clarify create emitters are per consumer (#6535)
• Add marbles to X.fromSupplier (#6531)
• Sync up with 2.2.10 snapshot (#6507)
• Merge in changes from 2.x since the initial branching (#6498)

Other

• Remove Changes.md (#6533)
• Remove test from testXXX method names, create a validator (#6525)
• Sync up with 2.2.10 snapshot (#6507)
• Merge in changes from 2.x since the initial branching (#6498)

Maven

Bugfixes

• Pull 6499: Add missing null check to BufferExactBoundedObserver.
• Pull 6505: Fix publish().refCount() hang due to race.
• Pull 6522: Fix concatMapDelayError not continuing on fused inner source crash.

Documentation changes

• Pull 6496: Fix outdated links in Additional-Reading.md.
• Pull 6497: Fix links in Alphabetical-List-of-Observable-Operators.md.
• Pull 6504: Fix various Javadocs & imports.
• Pull 6506: Expand the Javadoc of Flowable.
• Pull 6510: Correct "Reactive-Streams" to "Reactive Streams" in documentation.

Maven

Bugfixes

• Pull 6488: Fix zip not stopping the subscription upon eager error.

Documentation changes

• Pull 6453: Fixed wrong type referenced in Maybe and Single JavaDocs.
• Pull 6458: Update the Javadoc of the retry operator.

Other

• Pull 6452: Remove dependency of Schedulers from ObservableRefCount.
• Pull 6461: Change error message in ObservableFromArray.
• Pull 6469: Remove redundant methods from sample(Observable).
• Pull 6470: Remove unused import from Flowable.java.
• Pull 6485: Remove unused else from the Observable.

Maven

Bugfixes

• Pull 6442: Add missing undeliverable error handling logic for Completable.fromRunnable & fromAction operators.

Documentation changes

• Pull 6432: Improve the docs of CompositeDisposable.
• Pull 6434: Improve subjects and processors package doc.
• Pull 6436: Improve Creating-Observables wiki doc.

Other

• Pull 6433: Make error messages of parameter checks consistent.

Maven

API enhancements

• Pull 6386: Add doOnTerminate to Single/Maybe for consistency.

Bugfixes

• Pull 6405: Fix concatEager to dispose sources & clean up properly.
• Pull 6398: Fix window() with start/end selector not disposing/cancelling properly.

Documentation changes

• Pull 6377: Expand Observable#debounce and Flowable#debounce javadoc.
• Pull 6408: Improving Javadoc of flattenAsFlowable and flattenAsObservable methods.

Maven

API enhancements

• Pull 6370: Add interruptible mode via the new Schedulers.from(Executor, boolean) overload.

Bugfixes

• Pull 6359: Fix the error/race in Observable.repeatWhen due to flooding repeat signal.
• Pull 6362 : Fix Completable.andThen(Completable) not running on observeOn's Scheduler.
• Pull 6364: Fix Flowable.publish not requesting upon client change.
• Pull 6371: Fix bounded replay() memory leak due to bad node retention.
• Pull 6375: Don't dispose the winner of {Single|Maybe|Completable}.amb().
• Pull 6380: Fix CompositeException.getRootCause() detecting loops in the cause graph.

Documentation changes

• Pull 6365: Indicate source disposal in timeout(fallback).

Other changes

• Pull 6353: Use ignoreElement to convert Single to Completable in the README.md.

Maven

Documentation changes

• Pull 6344: Use correct return type in JavaDocs documentation in elementAtOrDefault.
• Pull 6346: Fix JavaDoc examples using markdown instead of @code.

Wiki changes

• Pull 6324: Java 8 version for Problem-Solving-Examples-in-RxJava.
• Pull 6343: Update Filtering Observables docs.
• Pull 6351: Updated java example in How-To-Use-RxJava.md file with java 8 version.

Other changes

• Pull 6313: Adding @NonNull annotation factory methods.
• Pull 6335: Replace indexed loop with for-each java5 syntax.

Maven

API changes

• Pull 6278: Add Maybe/Single/Completable materialize operator,
• Pull 6278: Add Single.dematerialize(selector) operator.
• Pull 6281: Add Flowable/Observable dematerialize(selector) operator.

Bugfixes

• Pull 6258: Fix cancel/dispose upon upstream switch for some operators.
• Pull 6269: Call the doOn{Dispose|Cancel} handler at most once.
• Pull 6283: Fix Observable.flatMap to sustain concurrency level.
• Pull 6297: Fix refCount eager disconnect not resetting the connection.

Documentation changes

• Pull 6280: Improve the package docs of io.reactivex.schedulers.
• Pull 6301: Add missing onSubscribe null-checks to NPE docs on Flowable/Observable subscribe.
• Pull 6303: Fix incorrect image placement in Flowable.zip docs.
• Pull 6305: Explain the non-concurrency requirement of the Emitter interface methods.
• Pull 6308: Explain the need to consume both the group sequence and each group specifically with Flowable.groupBy.
• Pull 6311: Explain that distinctUntilChanged requires non-mutating data to work as expected.

Wiki changes

• Pull 6260: Add generate examples to Creating-Observables.md.
• Pull 6267: Fix Creating-Observables.md docs stlye mistake.
• Pull 6273: Fix broken markdown of How-to-Contribute.md.
• Pull 6266: Update Error Handling Operators docs.
• Pull 6291: Update Transforming Observables docs.

Other changes

• Pull 6262: Use JUnit's assert format for assert messages for better IDE interoperation.
• Pull 6263: Inline SubscriptionHelper.isCancelled().
• Pull 6275: Improve the Observable/Flowable cache() operators.
• Pull 6287: Expose the Keep-Alive value of the IO Scheduler as System property.
• Pull 6321: Fix Flowable.toObservable backpressure annotation.

Maven

API changes

• Pull 6242: Add timed Completable.delaySubscription() operator.

Documentation changes

• Pull 6220: Remove unnecessary 's' from ConnectableObservable.
• Pull 6241: Remove mention of io.reactivex.functions.Functions nonexistent utility class.

Other changes

• Pull 6232: Cleanup Observable.flatMap drain logic.
• Pull 6234: Add timeout and unit to TimeoutException message in the timeout operators.
• Pull 6236: Adjust UndeliverableException and OnErrorNotImplementedException message to use the full inner exception.
• Pull 6244: Add @Nullable annotations for blocking methods in Completable.

Maven

Summary

Version 2.2.0 is the next minor release of the 2.x era and contains the standardization of many experimental API additions from the past year since version 2.1.0. Therefore, the following components are now considered stable and will be supported throughout the rest of the life of RxJava 2.x.

Classes, Enums, Annotations

• Annotation: N/A
• Subject: MulticastProcessor
• Classes: ParallelFlowable, UndeliverableException, OnErrorNotImplementedException
• Enum: ParallelFailureHandling
• Interfaces: {Completable|Single|Maybe|Observable|Flowable|Parallel}Emitter, {Completable|Single|Maybe|Observable|Flowable|Parallel}Converter, LambdaConsumerIntrospection, ScheduledRunnableIntrospection

Operators

• Flowable: as, concatMap{Single|Maybe|Completable}, limit, parallel, switchMap{Single|Maybe|Completable}, throttleLatest
• Observable: as, concatMap{Single|Maybe|Completable}, switchMap{Single|Maybe|Completable}, throttleLatest
• Single: as, mergeDelayError, onTerminateDetach, unsubscribeOn
• Maybe: as, mergeDelayError, switchIfEmpty
• Completable: as, fromMaybe, onTerminateDetach, takeUntil
• ParallelFlowable: as, map|filter|doOnNext(errorHandling)˙, sequentialDelayError
• Connectable{Flowable, Observable}: refCount(count + timeout)
• Subject/FlowableProcessor: offer, cleanupBuffer, create(..., delayError)
• Test{Observer, Subscriber}: assertValueAt, assertValuesOnly, assertValueSetOnly

(For the complete list and details on the promotions, see PR 6105.)

Release 2.2.0 is functionally identical to 2.1.17. Also to clarify, just like with previous minor version increments with RxJava, there won't be any further development or updates on the version 2.1.x (patch) level.

Other promotions

All Experimental/Beta APIs introduced up to version 2.1.17 are now standard with 2.2.

Project statistics

• Unique contributors: 75
• Issues closed: 283
• Bugs reported: 20
  • by community: 19 (95%)
• Commits: 320
• PRs: 296
  • PRs accepted: 268 (90.54%)
  • Community PRs: 96 (35.82% of all accepted)
• Bugs fixed: 39
  • by community: 8 (20.51%)
• Documentation enhancements: 117
  • by community: 40 (34.19%)
• Cleanup: 50
  • by community: 21 (42%)
• Performance enhancements: 12
  • by community: 1 (8.33%)
• Lines
  • added: 70,465
  • removed: 12,373

Acknowledgements

The project would like to thank the following contributors for their work on various code and documentation improvements (in the order they appear on the commit page):

@lcybo, @jnlopar, @UMFsimke, @apodkutin, @sircelsius,
@romanzes, @Kiskae, @RomanWuattier, @satoshun, @hans123456,
@fjoshuajr, @davidmoten, @vanniktech, @antego, @strekha,
@artfullyContrived, @VeskoI, @Desislav-Petrov, @Apsaliya, @sidjain270592,
@Milack27, @mekarthedev, @kjkrum, @zhyuri, @artem-zinnatullin,
@vpriscan, @aaronhe42, @adamsp, @bangarharshit, @zhukic,
@afeozzz, @btilbrook-nextfaze, @eventualbuddha, @shaishavgandhi05, @lukaszguz,
@runningcode, @kimkevin, @JakeWharton, @hzsweers, @ggikko,
@philleonard, @sadegh, @dsrees, @benwicks, @dweebo,
@dimsuz, @levaja, @takuaraki, @PhilGlass, @bmaslakov,
@tylerbwong, @AllanWang, @NickFirmani, @plackemacher, @matgabriel,
@jemaystermind, @ansman, @Ganapathi004, @leonardortlima, @pwittchen,
@youngam, @Sroka, @serj-lotutovici, @nathankooij, @mithunsasidharan,
@devisnik, @mg6maciej, @Rémon S, @hvesalai, @kojilin,
@ragunathjawahar, @brucezz, @paulblessing, @cypressf, @langara

(75 contributors)

The project would also thank its tireless reviewer @vanniktech for all his efforts on verifying and providing feedback on the many PRs from the project lead himself. 👍

Maven

API changes

• Pull 6079: Add Completable.takeUntil(Completable) operator.
• Pull 6085: Add Completable.fromMaybe operator.

Performance improvements

• Pull 6096: Improve Completable.delay operator internals.

Documentation changes

• Pull 6066: Fix links for Single class.
• Pull 6070: Adjust JavaDocs dl/dd entry stylesheet.
• Pull 6080: Improve class JavaDoc of Single, Maybe and Completable.
• Pull 6102: Adjust JavaDoc stylesheet of dt/dd within the method details.
• Pull 6103: Fix Completable mergeX JavaDoc missing dt before dd.
• Pull 6104: Fixing javadoc's code example of Observable#lift.
• Marble diagrams (Tracking issue 5789)
  • Pull 6074: Single.never method.
  • Pull 6075: Single.filter method.
  • Pull 6078: Maybe.hide marble diagram.
  • Pull 6076: Single.delay method.
  • Pull 6077: Single.hide operator.
  • Pull 6083: Add Completable marble diagrams (07/17a).
  • Pull 6081: Single.repeat operators.
  • Pull 6085: More Completable marbles.
  • Pull 6084: Single.repeatUntil operator.
  • Pull 6090: Add missing Completable marbles (+17, 07/18a).
  • Pull 6091: Single.amb operators.
  • Pull 6097: Add missing Completable marbles (+19, 07/19a).
  • Pull 6098: Several more Completable marbles (7/19b).
  • Pull 6101: Final set of missing Completable marbles (+26).

Maven

This is a hotfix release for a late-identified issue with concatMapMaybe and concatMapSingle.

Bugfixes

• Pull 6060: Fix concatMap{Single|Maybe} null emission on success-dispose race.

Maven

API changes

• Pull 6026: Add blockingSubscribe overload with prefetch amount allowing bounded backpressure.
• Pull 6052: Change {PublishSubject|PublishProcessor}.subscribeActual to protected. They were accidentally made public and there is no reason to call them outside of RxJava internals.

Documentation changes

• Pull 6031: Inline CompositeDisposable JavaDoc.
• Pull 6042: Fix MulticastProcessor JavaDoc comment.
• Pull 6049: Make it explicit that throttleWithTimout is an alias of debounce.
• Pull 6053: Add Maybe marble diagrams 06/21/a
• Pull 6057: Use different wording on blockingForEach() JavaDocs.
• Pull 6054: Expand {X}Processor JavaDocs by syncing with {X}Subject docs.

Performance enhancements

• Pull 6021: Add full implementation for Single.flatMapPublisher so it doesn't batch requests.
• Pull 6024: Dedicated {Single|Maybe}.flatMap{Publisher|Observable} & andThen(Observable|Publisher) implementations.
• Pull 6028: Improve Observable.takeUntil.

Bugfixes

• Pull 6019: Fix Single.takeUntil, Maybe.takeUntil dispose behavior.
• Pull 5947: Fix groupBy eviction so that source is cancelled and reduce volatile reads.
• Pull 6036: Fix disposed LambdaObserver.onError to route to global error handler.
• Pull 6045: Fix check in BlockingSubscriber that would always be false due to wrong variable.

Other changes

• Pull 6022: Add TCK for MulticastProcessor & {0..1}.flatMapPublisher
• Pull 6029: Upgrade to Gradle 4.3.1, add TakeUntilPerf.
• Pull 6033: Update & fix grammar of DESIGN.md

Maven

API changes

• Pull 5976: Add Single.concatEager().
• Pull 5986: Add ConnectableObservable.refCount() and ConnectableFlowable.refCount() with minimum consumer count & disconnect grace period.
• Pull 5979: Add Observable.throttleLatest and Flowable.throttleLatest().
• Pull 6002: Add MulticastProcessor.
• Pull 6010: Add assertValueSetOnly and assertValueSequenceOnly to TestObserver/TestSubscriber.

Deprecations

• Pull 5982: Deprecate getValues() in Subjects/FlowableProcessors to be removed in 3.x.

Documentation changes

• Pull 5977: Maybe/Single JavaDocs; annotation cleanup.
• Pull 5981: Improve JavaDocs of the subscribeActual methods.
• Pull 5984: Add blockingSubscribe JavaDoc clarifications.
• Pull 5987: Add marble diagrams to some Single.doOnX methods.
• Pull 5992: Observable javadoc cleanup.

Bugfixes

• Pull 5975: Fix refCount() connect/subscribe/cancel deadlock.
• Pull 5978: Flowable.take to route post-cancel errors to plugin error handler.
• Pull 5991: Fix switchMap to indicate boundary fusion.

Other changes

• Pull 5985: Cleanup in the Scheduler class.
• Pull 5996: Automatically publish the generated JavaDocs from CI.
• Pull 5995: Implement toString method for some Emitters.
• Pull 6005: JavaDocs HTML formatting and whitespace cleanup.
• Pull 6014: Fix & prevent null checks on primitives.

Release candidate for 2.1.14 testing the automatic JavaDoc pushback for release mode.

Please ignore this release and any subsequent RCx in case the pushback doesn't work properly.

Maven

API changes

• Pull 5957: Add Single.ignoreElement, deprecate Single.toCompletable (will be removed in 3.0).

Documentation changes

• Pull 5936: Fix Completable.toMaybe() @return javadoc.
• Pull 5948: Fix Observable javadoc mentioning doOnCancel instead of doOnDispose.
• Pull 5951: Update blockingX JavaDoc to mention wrapping of checked Exceptions.

Bugfixes

• Pull 5952: Fixed conditional iteration breaking in AppendOnlyLinkedArrayList.forEachWhile.
• Pull 5972: Fix Observable.concatMapSingle dropping upstream items.

Other changes

• Pull 5930: Add @NonNull annotations to create methods of Subjects and Processors.
• Pull 5940: Allow @SchedulerSupport annotation on constructors.
• Pull 5942: Removed TERMINATED check in PublishSubject.onNext and PublishProcessor.onNext.
• Pull 5959: Fix some typos and grammar mistakes.

Maven

RxJava 1.x is now officially end-of-life (EOL). No further developments, bugfixes, enhancements, javadoc changes or maintenance will be provided by this project after version 1.3.8 and after today.

Users are encouraged to migrate to 2.x. In accordance, the wiki will be updated in the coming months to describe 2.x features and properties.

Bugfixes

• Pull 5935: Fix take() to route late errors to RxJavaHooks.

Maven

Bugfixes

• Pull 5928: Fix concatMapSingle & concatMapMaybe dispose-cleanup crash.

Maven

API changes

• Pull 5871: Add Flowable.concatMapCompletable{DelayError} operator.
• Pull 5870: Add Flowable.switchMapCompletable{DelayError} operator.
• Pull 5872: Add Flowable.concatMap{Maybe,Single}{DelayError} operators.
• Pull 5873: Add Flowable.switchMap{Maybe,Single}{DelayError} operators.
• Pull 5875: Add Observable switchMapX and concatMapX operators.
• Pull 5906: Add public constructor for TestScheduler that takes the initial virtual time.

Performance enhancements

• Pull 5915: Optimize Observable.concatMapCompletable.
• Pull 5918: Improve the scalar source performance of Observable.(concat|switch)Map{Completable|Single|Maybe}.
• Pull 5919: Add fusion to Observable.switchMap inner source.

Documentation changes

• Pull 5863: Expand the documentation of the Flowable.lift() operator.
• Pull 5865: Improve the JavaDoc of the other lift() operators.
• Pull 5876: Add note about NoSuchElementException to Single.zip().
• Pull 5897: Clarify dematerialize() and terminal items/signals.
• Pull 5895: Fix buffer() documentation to correctly describe onError behavior.

Bugfixes

• Pull 5887: Fix window(Observable|Callable) upstream handling.
• Pull 5888: Fix Flowable.window(Publisher|Callable) upstream handling.
• Pull 5892: Fix the extra retention problem in ReplaySubject.
• Pull 5900: Fix Observable.flatMap scalar maxConcurrency overflow.
• Pull 5893: Fix publish(-|Function) subscriber swap possible data loss.
• Pull 5898: Fix excess item retention in the other replay components.
• Pull 5904: Fix Flowable.singleOrError().toFlowable() not signalling NoSuchElementException.
• Pull 5883: Fix FlowableWindowBoundary not cancelling the upstream on a missing backpressure case, causing NullPointerException.

Other changes

• Pull 5890: Added @Nullable annotations to subjects.
• Pull 5886: Upgrade the algorithm of Observable.timeout(time|selector) operators.
• Coverage improvements
  • Pull 5883: Improve coverage and fix small mistakes/untaken paths in operators.
  • Pull 5889: Cleanup, coverage and related component fixes
  • Pull 5891: Improve coverage & related cleanup 03/05.
  • Pull 5905: Coverage improvements, logical fixes and cleanups 03/08.
  • Pull 5910: Improve coverage, fix operator logic 03/12.

Maven

API changes

• Pull 5845: Add efficient concatWith(Single|Maybe|Completable) overloads to Flowable and Observable.
• Pull 5847: Add efficient mergeWith(Single|Maybe|Completable) overloads to Flowable and Observable.
• Pull 5860: Add Flowable.groupBy overload with evicting map factory.

Documentation changes

• Pull 5824: Improve the wording of the share() JavaDocs.
• Pull 5826: Fix Observable.blockingIterable(int) and add Observable.blockingLatest marbles.
• Pull 5828: Document size-bounded replay emission's item retention property.
• Pull 5830: Reword the just() operator and reference other typical alternatives.
• Pull 5834: Fix copy-paste errors in SingleSubject JavaDoc.
• Pull 5837: Detail distinct() and distinctUntilChanged() in JavaDoc.
• Pull 5841: Improve JavaDoc of Observer, SingleObserver, MaybeObserver and CompletableObserver.
• Pull 5843: Expand the JavaDocs of the Scheduler API.
• Pull 5844: Explain the properties of the {Flowable|Observable|Single|Maybe|Completable}Emitter interfaces in detail.
• Pull 5848: Improve the wording of the Maybe.fromCallable JavaDoc.
• Pull 5856: Add finite requirement to various collector operators' JavaDoc.

Bugfixes

• Pull 5833: Fix Observable.switchMap main onError not disposing the current inner source.

Other changes

• Pull 5838: Added nullability annotation for completable assembly.
• Pull 5858: Remove unnecessary comment from Observable.timeInterval(TimeUnit).

Maven

Bugfixes

• Pull 5850: Fix a race condition that may make OperatorMaterialize emit the wrong signals.
• Pull 5851: Fix a race condition in OperatorMerge.InnerSubscriber#onError causing incorrect terminal event.

Maven

Other

• Pull 5820: RxJavaPlugins lookup workaround for System.getProperties() access restrictions.

Maven

API changes

• Pull 5799: Add missing {Maybe|Single}.mergeDelayError variants.

Performance improvements

• Pull 5790: Improve request accounting overhead in Flowable retry/repeat.

Documentation changes

• Pull 5783: Fix JavaDoc wording of onTerminateDetach.
• Pull 5780: Improve BehaviorSubject JavaDoc + related clarifications.
• Pull 5781: Describe merge() error handling.
• Pull 5785: Update Maybe doOn{Success,Error,Complete} JavaDoc.
• Pull 5786: Add error handling section to merge() operator JavaDocs.
• Pull 5802: Improved XSubject JavaDocs.
• Marble diagram fixes to Observable:
  • Pull 5795: More marbles 01/08-a.
  • Pull 5797: Observable marble fixes 01/08-b.
  • Pull 5798: Observable.replay(Function, ...) marble fixes.
  • Pull 5804: More Observable marbles, 01/10-a.
  • Pull 5805: Final planned Observable marble additions/fixes.
• Pull 5816: Add Subject and Processor marbles.

Bugfixes

• Pull 5792: Fix flatMap inner fused poll crash not cancelling the upstream.
• Pull 5811: Fix buffer(open, close) not disposing indicators properly.