https://developers.google.com/j2objc/javadoc/jre/reference/java/util/concurrent/ExecutorCompletionService
ExecutorCompletionService | J2ObjC | Google for Developers
googledevelopers
https://docs.oracle.com/javase/jp/21/docs/api/java.base/java/util/concurrent/ExecutorCompletionService.html
ExecutorCompletionService (Java SE 21 & JDK 21)
declaration: module: java.base, package: java.util.concurrent, class: ExecutorCompletionService
java sejdk