[Java] Update ActiveJ to v4.0 (#6376)

frameworks/Java/activej/activej.dockerfile

@@ -8,4 +8,4 @@ RUN mvn compile assembly:single -q
 FROM openjdk:11.0.3-jdk-slim
 WORKDIR /activej
 COPY --from=maven /activej/target/activej-server-benchmark-0.0.1-SNAPSHOT-jar-with-dependencies.jar app.jar
-CMD ["java", "-Xms2G", "-Xmx2G", "-server", "-XX:+UseNUMA", "-XX:+UseParallelGC", "-XX:+AggressiveOpts", "-DHttpHeadersMultimap.initialSize=16", "-jar", "app.jar"]
+CMD ["java", "-Xms2G", "-Xmx2G", "-server", "-XX:+UseNUMA", "-XX:+UseParallelGC", "-XX:+AggressiveOpts", "-DHttpServerConnection.initialWriteBufferSize=4096", "-DHttpHeadersMultimap.initialSize=16", "-jar", "app.jar"]

frameworks/Java/activej/pom.xml

@@ -46,7 +46,7 @@
 		<dependency>
 			<groupId>io.activej</groupId>
 			<artifactId>activej-launchers-http</artifactId>
-			<version>4.0-beta1</version>
+			<version>4.0</version>
 		</dependency>
 		<dependency>
 			<groupId>com.dslplatform</groupId>