process-api.yaml

---
id: 53
slug: "process-api"
title: "Modern Process API"
category: "concurrency"
difficulty: "intermediate"
jdkVersion: "9"
oldLabel: "Java 8"
modernLabel: "Java 9+"
oldApproach: "Runtime.exec()"
modernApproach: "ProcessHandle"
oldCode: |-
  Process p = Runtime.getRuntime()
      .exec("ls -la");
  int code = p.waitFor();
  // no way to get PID
  // no easy process info
modernCode: |-
  ProcessHandle ph =
      ProcessHandle.current();
  long pid = ph.pid();
  ph.info().command()
      .ifPresent(IO::println);
  ph.children().forEach(
      c -> IO.println(c.pid()));
summary: "Inspect and manage OS processes with ProcessHandle."
explanation: "ProcessHandle provides PIDs, process info (command, arguments, start\
  \ time, CPU usage), parent/child relationships, and process destruction. No more\
  \ undocumented Process internals."
whyModernWins:
- icon: "🔍"
  title: "Full info"
  desc: "Access PID, command, arguments, start time, CPU usage."
- icon: "🌳"
  title: "Process tree"
  desc: "Navigate parent, children, and descendants."
- icon: "📊"
  title: "Monitoring"
  desc: "onExit() returns a CompletableFuture for async monitoring."
support:
  state: "available"
  description: "Widely available since JDK 9 (Sept 2017)"
prev: "concurrency/thread-sleep-duration"
next: "concurrency/concurrent-http-virtual"
related:
- "concurrency/scoped-values"
- "concurrency/concurrent-http-virtual"
- "concurrency/completablefuture-chaining"
docs:
- title: "ProcessHandle"
  href: "https://docs.oracle.com/en/java/javase/25/docs/api/java.base/java/lang/ProcessHandle.html"
- title: "Process API (JEP 102)"
  href: "https://openjdk.org/jeps/102"