picocli VS RxJava

Picocli allows using a compiler annotation processor to generate classes at compile time instead [0].

[0]: https://github.com/remkop/picocli/blob/main/picocli-codegen/...

Picocli is a pretty good one for writing CLI apps

"and there are simply no good command line input parsing libraries for Java."

Looks like author missed the most obvious and popular OSS one: https://picocli.info/

The command line example gave me the "ick". It is usually preferrable to parse the command line arguments into one instance of a custom "command class", rather than into a list of things. Like jcommander, picocli or jbock do.

Complex argument parsing needs to be auto-generated by libraries like picocli. Even if you need something custom, it'd be quicker to write an Annotation processor from scratch than editing that file.

https://github.com/remkop/picocli

"Picocli-based applications can be ahead-of-time compiled to a GraalVM native image, with extremely fast startup time and lower memory requirements, which can be distributed as a single executable file."

https://picocli.info/quick-guide.html

Using picocli to handle your command line options gives you the best chance to automatically generate an ArgumentCompleter script in the future, but won't help you today (other than possibly making your command line handling more standardized & easier).

Picocli

Then we released a JBang! and picocli based cli that would be, on any OS running a jvm runtime :

picocli : "a mighty tiny command line interface"

Is this similar RxJava, the reactive extensions library for https://github.com/ReactiveX/RxJava ? I have made that work in Clojure in production.

Since you mentioned java, there is RxJava and RxAndroid. Google general recommendation now is to use kotlin coroutines if you're considering writing your app with that.

It's very quick though. In terms of the correctness of the syntax, I've never seen an issue while translating a single file or a single function. When I took the entire RxJava code base 5 years ago, right clicked on the source folder and converted to Kotlin, I found lots of problems. File by file I've never seen any issues though, but I also haven't done it much.

You all beat me to MapStruct and Testcontainers. Honorable mention to RxJava, which I use in Desktop apps.

RxJava with RxRelay (and rx-combinetuple-kt)

RxJava2

More information about rxJava, check it out here: (HERE)[https://github.com/ReactiveX/RxJava]

Concurrency: Kotlin coroutines for general use, Rx or Flow for reactive programming (you can technically use Rx for regular concurrency as well, but not really what it's meant for)

If you're just looking at making a service call on a regular interval and notifying the user when there's an actual change in data, you can also look into RxJava https://github.com/ReactiveX/RxJava. From here you can "subscribe" to your service call, and then every time you make your service call you can have it look for changes compared to the previous emission .distinctUntilChanged() and then only notify it's subscribers when it notices an actual change. From there you can trigger a local notification and push to a LiveData (assuming MVVM) or otherwise update the UI to match as well.

``` io.reactivex.rxjava3.exceptions.OnErrorNotImplementedException: The exception was not handled due to missing onError handler in the subscribe() method call. Further reading: https://github.com/ReactiveX/RxJava/wiki/Error-Handling | java.lang.IllegalStateException: Migration didn't properly handle: feed_group(org.schabi.newpipe.database.feed.model.FeedGroupEntity). Expected: TableInfo{name='feed_group', columns={name=Column{name='name', type='TEXT', affinity='2', notNull=true, primaryKeyPosition=0, defaultValue='null'}, uid=Column{name='uid', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=1, defaultValue='null'}, icon_id=Column{name='icon_id', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=0, defaultValue='null'}, sort_order=Column{name='sort_order', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=0, defaultValue='null'}}, foreignKeys=[], indices=[Index{name='index_feed_group_sort_order', unique=false, columns=[sort_order]}]} Found: TableInfo{name='feed_group', columns={uid=Column{name='uid', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=1, defaultValue='null'}, name=Column{name='name', type='TEXT', affinity='2', notNull=true, primaryKeyPosition=0, defaultValue='null'}, icon_id=Column{name='icon_id', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=0, defaultValue='null'}, sort_order=Column{name='sort_order', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=0, defaultValue='0'}}, foreignKeys=[], indices=[]} at io.reactivex.rxjava3.internal.functions.Functions$OnErrorMissingConsumer.accept(Functions.java:717) at io.reactivex.rxjava3.internal.functions.Functions$OnErrorMissingConsumer.accept(Functions.java:714) at io.reactivex.rxjava3.internal.subscribers.LambdaSubscriber.onError(LambdaSubscriber.java:79) at io.reactivex.rxjava3.internal.operators.flowable.FlowableObserveOn$BaseObserveOnSubscriber.checkTerminated(FlowableObserveOn.java:209) at io.reactivex.rxjava3.internal.operators.flowable.FlowableObserveOn$ObserveOnSubscriber.runAsync(FlowableObserveOn.java:394) at io.reactivex.rxjava3.internal.operators.flowable.FlowableObserveOn$BaseObserveOnSubscriber.run(FlowableObserveOn.java:176) at io.reactivex.rxjava3.android.schedulers.HandlerScheduler$ScheduledRunnable.run(HandlerScheduler.java:123) at android.os.Handler.handleCallback(Handler.java:938) at android.os.Handler.dispatchMessage(Handler.java:99) at android.os.Looper.loop(Looper.java:223) at android.app.ActivityThread.main(ActivityThread.java:7665) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:594) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947) Caused by: java.lang.IllegalStateException: Migration didn't properly handle: feed_group(org.schabi.newpipe.database.feed.model.FeedGroupEntity). Expected: TableInfo{name='feed_group', columns={name=Column{name='name', type='TEXT', affinity='2', notNull=true, primaryKeyPosition=0, defaultValue='null'}, uid=Column{name='uid', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=1, defaultValue='null'}, icon_id=Column{name='icon_id', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=0, defaultValue='null'}, sort_order=Column{name='sort_order', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=0, defaultValue='null'}}, foreignKeys=[], indices=[Index{name='index_feed_group_sort_order', unique=false, columns=[sort_order]}]} Found: TableInfo{name='feed_group', columns={uid=Column{name='uid', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=1, defaultValue='null'}, name=Column{name='name', type='TEXT', affinity='2', notNull=true, primaryKeyPosition=0, defaultValue='null'}, icon_id=Column{name='icon_id', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=0, defaultValue='null'}, sort_order=Column{name='sort_order', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=0, defaultValue='0'}}, foreignKeys=[], indices=[]} at androidx.room.RoomOpenHelper.onUpgrade(RoomOpenHelper.java:103) at androidx.sqlite.db.framework.FrameworkSQLiteOpenHelper$OpenHelper.onUpgrade(FrameworkSQLiteOpenHelper.java:177) at android.database.sqlite.SQLiteOpenHelper.getDatabaseLocked(SQLiteOpenHelper.java:416) at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:316) at androidx.sqlite.db.framework.FrameworkSQLiteOpenHelper$OpenHelper.getWritableSupportDatabase(FrameworkSQLiteOpenHelper.java:145) at androidx.sqlite.db.framework.FrameworkSQLiteOpenHelper.getWritableDatabase(FrameworkSQLiteOpenHelper.java:106) at androidx.room.RoomDatabase.inTransaction(RoomDatabase.java:622) at androidx.room.RoomDatabase.assertNotSuspendingTransaction(RoomDatabase.java:399) at androidx.room.RoomDatabase.query(RoomDatabase.java:442) at androidx.room.util.DBUtil.query(DBUtil.java:83) at org.schabi.newpipe.database.feed.dao.FeedDAO_Impl$7.call(FeedDAO_Impl.java:285) at org.schabi.newpipe.database.feed.dao.FeedDAO_Impl$7.call(FeedDAO_Impl.java:282) at io.reactivex.rxjava3.internal.operators.maybe.MaybeFromCallable.subscribeActual(MaybeFromCallable.java:47) at io.reactivex.rxjava3.core.Maybe.subscribe(Maybe.java:5330) at io.reactivex.rxjava3.internal.operators.flowable.FlowableFlatMapMaybe$FlatMapMaybeSubscriber.onNext(FlowableFlatMapMaybe.java:131) at io.reactivex.rxjava3.internal.operators.flowable.FlowableObserveOn$ObserveOnSubscriber.runAsync(FlowableObserveOn.java:402) at io.reactivex.rxjava3.internal.operators.flowable.FlowableObserveOn$BaseObserveOnSubscriber.run(FlowableObserveOn.java:176) at io.reactivex.rxjava3.internal.schedulers.ExecutorScheduler$ExecutorWorker$BooleanRunnable.run(ExecutorScheduler.java:322) at io.reactivex.rxjava3.internal.schedulers.ExecutorScheduler$ExecutorWorker.runEager(ExecutorScheduler.java:287) at io.reactivex.rxjava3.internal.schedulers.ExecutorScheduler$ExecutorWorker.run(ExecutorScheduler.java:248) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641) at java.lang.Thread.run(Thread.java:923)