Update RxJava 3 -> RxJava 4 texts

Author: akarnokd

DESIGN.md

@@ -586,7 +586,7 @@ interface QueueSubscription<T> implements Queue<T>, Subscription {
 
 For performance, the mode is an integer bitflags setup, called early during subscription time, and allows negotiating the fusion mode. Usually, producers can do only one mode and consumers can do both mode. Because fused, intermediate operators attach logic (which is many times user-callback) to the exit point of the queue interface (poll()), it may change the computation location of those callbacks in an unwanted way. The flag `BOUNDARY` is added by consumers indicating that they will consume the queue over an async boundary. Intermediate operators, such as `map` and `filter` then can reject the fusion in such sequences.
 
-Since RxJava 3.x is still JDK 6 compatible, the `QueueSubscription` can't itself default unnecessary methods and implementations are required to throw `UnsupportedOperationException` for `Queue` methods other than the following:
+Since RxJava 4.x is still JDK 26 compatible, the `QueueSubscription` can't itself default unnecessary methods and implementations are required to throw `UnsupportedOperationException` for `Queue` methods other than the following:
 
   - `poll()`.
   - `isEmpty()`.

README.md

@@ -48,10 +48,10 @@ The [1.x version](https://github.com/ReactiveX/RxJava/tree/1.x) is end-of-life a
 The first step is to include RxJava 4 into your project, for example, as a Gradle compile dependency:
 
 ```groovy
-implementation "io.reactivex.rxjava3:rxjava:3.x.y"
+implementation "io.reactivex.rxjava4:rxjava:4.x.y"
 ```
 
-(Please replace `x` and `y` with the latest version numbers: [![Maven Central](https://maven-badges.sml.io/sonatype-central/io.reactivex.rxjava3/rxjava/badge.svg)](https://maven-badges.sml.io/sonatype-central/io.reactivex.rxjava3/rxjava)
+(Please replace `x` and `y` with the latest version numbers: [![Maven Central](https://maven-badges.sml.io/sonatype-central/io.reactivex.rxjava4/rxjava/badge.svg)](https://maven-badges.sml.io/sonatype-central/io.reactivex.rxjava4/rxjava)
 )
 
 ### Hello World
@@ -70,11 +70,11 @@ public class HelloWorld {
 }
 ```
 
-Note that RxJava 3 components now live under `io.reactivex.rxjava3` and the base classes and interfaces live under `io.reactivex.rxjava4.core`.
+Note that RxJava 4 components now live under `io.reactivex.rxjava4` and the base classes and interfaces live under `io.reactivex.rxjava4.core`.
 
 ### Base classes
 
-RxJava 3 features several base classes you can discover operators on:
+RxJava 4 features several base classes you can discover operators on:
 
   - [`io.reactivex.rxjava4.core.Flowable`](http://reactivex.io/RxJava/4.x/javadoc/io/reactivex/rxjava4/core/Flowable.html): 0..N flows, supporting Reactive-Streams and backpressure
   - [`io.reactivex.rxjava4.core.Observable`](http://reactivex.io/RxJava/4.x/javadoc/io/reactivex/rxjava4/core/Observable.html): 0..N flows, no backpressure,
@@ -197,7 +197,7 @@ Typically, you can move computations or blocking IO to some other thread via `su
 
 ### Schedulers
 
-RxJava operators don't work with `Thread`s or `ExecutorService`s directly but with so-called `Scheduler`s that abstract away sources of concurrency behind a uniform API. RxJava 3 features several standard schedulers accessible via `Schedulers` utility class. 
+RxJava operators don't work with `Thread`s or `ExecutorService`s directly but with so-called `Scheduler`s that abstract away sources of concurrency behind a uniform API. RxJava 4 features several standard schedulers accessible via `Schedulers` utility class. 
 
 - `Schedulers.computation()`: Run computation intensive work on a fixed number of dedicated threads in the background. Most asynchronous operators use this as their default `Scheduler`.
 - `Schedulers.io()`: Run I/O-like or blocking operations on a dynamically changing set of threads.
@@ -470,7 +470,7 @@ Flowable<T> concatArrayEagerDelayError(Publisher<? extends T>... sources);
 
 #### Base class vs base type
 
-The base classes can be considered heavy due to the sheer number of static and instance methods on them. RxJava 3's design was heavily influenced by the [Reactive Streams](https://github.com/reactive-streams/reactive-streams-jvm#reactive-streams) specification, therefore, the library features a class and an interface per each reactive type:
+The base classes can be considered heavy due to the sheer number of static and instance methods on them. RxJava 4's design was heavily influenced by the [Reactive Streams](https://github.com/reactive-streams/reactive-streams-jvm#reactive-streams) specification, therefore, the library features a class and an interface per each reactive type:
 
 | Type | Class | Interface | Consumer |
 |------|-------|-----------|----------|
@@ -502,7 +502,7 @@ It is recommended one sets up the following `-dontwarn` entry in the application
 -dontwarn java.util.concurrent.Flow*
 ```
 
-For R8, the RxJava jar includes the `META-INF/proguard/rxjava3.pro` with the same no-warning clause and should apply automatically.
+For R8, the RxJava jar includes the `META-INF/proguard/rxjava4.pro` with the same no-warning clause and should apply automatically.
 
 ### Further reading
 
@@ -549,27 +549,27 @@ All code inside the `io.reactivex.rxjava4.internal.*` packages are considered pr
 
 ## Binaries
 
-Binaries and dependency information for Maven, Ivy, Gradle and others can be found at [http://search.maven.org](http://search.maven.org/#search%7Cga%7C1%7Cio.reactivex.rxjava3).
+Binaries and dependency information for Maven, Ivy, Gradle and others can be found at [http://search.maven.org](http://search.maven.org/#search%7Cga%7C1%7Cio.reactivex.rxjava4).
 
 Example for Gradle:
 
 ```groovy
-implementation 'io.reactivex.rxjava3:rxjava:x.y.z'
+implementation 'io.reactivex.rxjava4:rxjava:x.y.z'
 ```
 
 and for Maven:
 
 ```xml
 <dependency>
-    <groupId>io.reactivex.rxjava3</groupId>
+    <groupId>io.reactivex.rxjava4</groupId>
     <artifactId>rxjava</artifactId>
     <version>x.y.z</version>
 </dependency>
 ```
 and for Ivy:
 
 ```xml
-<dependency org="io.reactivex.rxjava3" name="rxjava" rev="x.y.z" />
+<dependency org="io.reactivex.rxjava4" name="rxjava" rev="x.y.z" />
 ```
 
 ### Snapshots
@@ -582,7 +582,7 @@ repositories {
 }
 
 dependencies {
-  implementation 'io.reactivex.rxjava3:rxjava:3.0.0-SNAPSHOT'
+  implementation 'io.reactivex.rxjava4:rxjava:4.0.0-SNAPSHOT'
 }
 ```
 

docs/Getting-Started.md

@@ -1,33 +1,33 @@
 ## Getting Binaries
 
-You can find binaries and dependency information for Maven, Ivy, Gradle, SBT, and others at [http://search.maven.org](https://search.maven.org/search?q=g:io.reactivex.rxjava3%20AND%20rxjava).
+You can find binaries and dependency information for Maven, Ivy, Gradle, SBT, and others at [http://search.maven.org](https://search.maven.org/search?q=g:io.reactivex.rxjava4%20AND%20rxjava).
 
 Example for Maven:
 
 ```xml
 <dependency>
-    <groupId>io.reactivex.rxjava3</groupId>
+    <groupId>io.reactivex.rxjava4</groupId>
     <artifactId>rxjava</artifactId>
-    <version>3.0.4</version>
+    <version>4.0.0</version>
 </dependency>
 ```
 and for Ivy:
 
 ```xml
-<dependency org="io.reactivex.rxjava3" name="rxjava" rev="3.0.4" />
+<dependency org="io.reactivex.rxjava4" name="rxjava" rev="4.0.0" />
 ```
 
 and for SBT:
 
 ```scala
 libraryDependencies += "io.reactivex" %% "rxscala" % "0.26.5"
 
-libraryDependencies += "io.reactivex.rxjava3" % "rxjava" % "3.0.4"
+libraryDependencies += "io.reactivex.rxjava4" % "rxjava" % "4.0.0"
 ```
 
 and for Gradle:
 ```groovy
-implementation 'io.reactivex.rxjava3:rxjava:3.0.4'
+implementation 'io.reactivex.rxjava4:rxjava:4.0.0'
 ```
 
 If you need to download the jars instead of using a build system, create a Maven `pom` file like this with the desired version:
@@ -38,17 +38,17 @@ If you need to download the jars instead of using a build system, create a Maven
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
       <modelVersion>4.0.0</modelVersion>
-      <groupId>io.reactivex.rxjava3</groupId>
+      <groupId>io.reactivex.rxjava4</groupId>
       <artifactId>rxjava</artifactId>
       <version>3.0.4</version>
       <name>RxJava</name>
       <description>Reactive Extensions for Java</description>
       <url>https://github.com/ReactiveX/RxJava</url>
       <dependencies>
           <dependency>
-              <groupId>io.reactivex.rxjava3</groupId>
+              <groupId>io.reactivex.rxjava4</groupId>
               <artifactId>rxjava</artifactId>
-              <version>3.0.4</version>
+              <version>4.0.0</version>
           </dependency>
       </dependencies>
 </project>
@@ -74,7 +74,7 @@ repositories {
 }
 
 dependencies {
-  implementation 'io.reactivex.rxjava3:rxjava:4.0.0-SNAPSHOT'
+  implementation 'io.reactivex.rxjava4:rxjava:4.0.0-SNAPSHOT'
 }
 ```
 

docs/Writing-operators-for-2.0.md

@@ -1574,7 +1574,7 @@ This is the level of the Reactive-Streams based libraries such as **Reactor 2**
 #### Generation 4
 This level expands upon the Reactive-Streams interfaces with operator-fusion (in a compatible fashion, that is, op-fusion is optional between two stages and works without them). **Reactor 3** and **RxJava 2** are at this level. The material around **Akka-Stream** mentions operator-fusion as well, however, **Akka-Stream** is not a native Reactive-Streams implementation (requires a materializer to get a `Publisher` out) and as such it is only Gen 3.
 
-There are discussions among the 4th generation library providers to have the elements of operator-fusion standardized in Reactive-Streams 2.0 specification (or in a neighboring extension) and have **RxJava 3** and **Reactor 4** work together on that aspect as well.
+There are discussions among the 4th generation library providers to have the elements of operator-fusion standardized in Reactive-Streams 2.0 specification (or in a neighboring extension) and have **RxJava 4** and **Reactor 4** work together on that aspect as well.
 
 ## Components
 

src/main/java/io/reactivex/rxjava4/core/FlowableSubscriber.java

@@ -18,7 +18,7 @@
 import io.reactivex.rxjava4.annotations.NonNull;
 
 /**
- * Represents a Reactive-Streams inspired {@link Subscriber} that is RxJava 3 only
+ * Represents a Reactive-Streams inspired {@link Subscriber} that is RxJava 4 only
  * and weakens the Reactive Streams rules <a href='https://github.com/reactive-streams/reactive-streams-jvm#1.3'>§1.3</a>
  * and <a href='https://github.com/reactive-streams/reactive-streams-jvm#3.9'>§3.9</a> of the specification
  * for gaining performance.

src/test/java/io/reactivex/rxjava4/internal/jdk8/FlowableCollectWithCollectorTest.java

@@ -103,7 +103,7 @@ public Supplier<Integer> supplier() {
 
             @Override
             public BiConsumer<Integer, Integer> accumulator() {
-                return (a, b) -> { throw new TestException(); };
+                return (_, _) -> { throw new TestException(); };
             }
 
             @Override
@@ -139,7 +139,7 @@ public Supplier<Integer> supplier() {
 
             @Override
             public BiConsumer<Integer, Integer> accumulator() {
-                return (a, b) -> {  };
+                return (_, _) -> {  };
             }
 
             @Override
@@ -149,7 +149,7 @@ public BinaryOperator<Integer> combiner() {
 
             @Override
             public Function<Integer, Integer> finisher() {
-                return a -> { throw new TestException(); };
+                return _ -> { throw new TestException(); };
             }
 
             @Override
@@ -185,7 +185,7 @@ public Supplier<Integer> supplier() {
 
                 @Override
                 public BiConsumer<Integer, Integer> accumulator() {
-                    return (a, b) -> { throw new TestException(); };
+                    return (_, _) -> { throw new TestException(); };
                 }
 
                 @Override
@@ -260,7 +260,7 @@ public Supplier<Integer> supplier() {
 
             @Override
             public BiConsumer<Integer, Integer> accumulator() {
-                return (a, b) -> { };
+                return (_, _) -> { };
             }
 
             @Override
@@ -297,7 +297,7 @@ public Supplier<Integer> supplier() {
 
             @Override
             public BiConsumer<Integer, Integer> accumulator() {
-                return (a, b) -> { throw new TestException(); };
+                return (_, _) -> { throw new TestException(); };
             }
 
             @Override
@@ -334,7 +334,7 @@ public Supplier<Integer> supplier() {
 
             @Override
             public BiConsumer<Integer, Integer> accumulator() {
-                return (a, b) -> {  };
+                return (_, _) -> {  };
             }
 
             @Override
@@ -344,7 +344,7 @@ public BinaryOperator<Integer> combiner() {
 
             @Override
             public Function<Integer, Integer> finisher() {
-                return a -> { throw new TestException(); };
+                return _ -> { throw new TestException(); };
             }
 
             @Override
@@ -381,7 +381,7 @@ public Supplier<Integer> supplier() {
 
                 @Override
                 public BiConsumer<Integer, Integer> accumulator() {
-                    return (a, b) -> { throw new TestException(); };
+                    return (_, _) -> { throw new TestException(); };
                 }
 
                 @Override

src/test/java/io/reactivex/rxjava4/internal/jdk8/ObservableCollectWithCollectorTest.java

@@ -70,7 +70,7 @@ public Supplier<Integer> supplier() {
 
             @Override
             public BiConsumer<Integer, Integer> accumulator() {
-                return (a, b) -> { };
+                return (_, _) -> { };
             }
 
             @Override
@@ -106,7 +106,7 @@ public Supplier<Integer> supplier() {
 
             @Override
             public BiConsumer<Integer, Integer> accumulator() {
-                return (a, b) -> { throw new TestException(); };
+                return (_, _) -> { throw new TestException(); };
             }
 
             @Override
@@ -142,7 +142,7 @@ public Supplier<Integer> supplier() {
 
             @Override
             public BiConsumer<Integer, Integer> accumulator() {
-                return (a, b) -> {  };
+                return (_, _) -> {  };
             }
 
             @Override
@@ -152,7 +152,7 @@ public BinaryOperator<Integer> combiner() {
 
             @Override
             public Function<Integer, Integer> finisher() {
-                return a -> { throw new TestException(); };
+                return _ -> { throw new TestException(); };
             }
 
             @Override
@@ -188,7 +188,7 @@ public Supplier<Integer> supplier() {
 
                 @Override
                 public BiConsumer<Integer, Integer> accumulator() {
-                    return (a, b) -> { throw new TestException(); };
+                    return (_, _) -> { throw new TestException(); };
                 }
 
                 @Override
@@ -263,7 +263,7 @@ public Supplier<Integer> supplier() {
 
             @Override
             public BiConsumer<Integer, Integer> accumulator() {
-                return (a, b) -> { };
+                return (_, _) -> { };
             }
 
             @Override
@@ -300,7 +300,7 @@ public Supplier<Integer> supplier() {
 
             @Override
             public BiConsumer<Integer, Integer> accumulator() {
-                return (a, b) -> { throw new TestException(); };
+                return (_, _) -> { throw new TestException(); };
             }
 
             @Override
@@ -337,7 +337,7 @@ public Supplier<Integer> supplier() {
 
             @Override
             public BiConsumer<Integer, Integer> accumulator() {
-                return (a, b) -> {  };
+                return (_, _) -> {  };
             }
 
             @Override
@@ -347,7 +347,7 @@ public BinaryOperator<Integer> combiner() {
 
             @Override
             public Function<Integer, Integer> finisher() {
-                return a -> { throw new TestException(); };
+                return _ -> { throw new TestException(); };
             }
 
             @Override
@@ -384,7 +384,7 @@ public Supplier<Integer> supplier() {
 
                 @Override
                 public BiConsumer<Integer, Integer> accumulator() {
-                    return (a, b) -> { throw new TestException(); };
+                    return (_, _) -> { throw new TestException(); };
                 }
 
                 @Override