Export of my JShell session from The Good, the Bad and the Ugly of Java API design talk at DevNexus 2020.

devnexus.jsh

Set<Integer> set = new HashSet<Integer>()
set.add(1)
set.add(2)
set.add(3)
set = Collections.unmodifiableSet(set)
Collections.unmodifiableSet(new HashSet<>Arrays.asList(1,2,3)))
Collections.unmodifiableSet(new HashSet<>Arrays.asList(1,2,3))
Collections.unmodifiableSet(new HashSet<>(Arrays.asList(1,2,3)))
Collections.unmodifiableSet(new HashSet<Integer>() {{ add(1); add(2); add(3); }})
ImmutableSet.of(1,2,3)
Set<Integer> set2 = new HashSet<Integer>(set)
set2.add(4)
Set<Integer> set2 = Collections.unmodifiableSet(new HashSet<Integer>(set))
set2.add(4)
Set.of(1,2,3)
Map.ofEntries(entry(1, "hello"))
Set<Integer> set2 = Set.copyOf(set)
set2.add(4)
List.copyOf(set)
set.stream().collect(toUnmodifiableList())
StackTraceElement[] st = new Throwable().getStackTrace()
Thread.currentThread().getStackTrace()
StackWalker.getInstance().walk(s -> s.collect(toList()
))
StackWalker.getInstance().walk(s -> s.limit(3).collect(toList()))
StackWalker.getInstance(Option.RETAIN_CLASS_REFERENCE).walk(s -> s.map(f -> f.getDeclaringClass()).collect(toList()))
new ProcessBuilder().command("jps").start()
new DefaultExecutor().execute(CommandLine.parse("jps"))
ProcessHandle.current().pid()
ProcessHandle.current().info()
ProcessHandle.current().info().commandLine()
ProcessHandle.allProcesses().map(p -> p.info().command()).collect(toList())
new ProcessBuilder().command("sleep", "3").start().toHandle().onExit().thenAccept(System.out::println)
ProcessBuilder jps = new ProcessBuilder().command("jps")
ProcessBuilder grep = new ProcessBuilder().command("grep", "JShell")
List<Process> pipeline = ProcessBuilder.startPipeline(List.of(jps, grep))
pipeline
pipeline.get(1).getInputStream().transferTo(System.out)
HttpHandler handler = he -> {
String body = "hello devnexus";
he.sendResponseHeaders(200, body.length());

try (OutputStream os = he.getResponseBody()) {
os.write(body.getBytes());
}
}
/l
HttpServer hs = HttpServer.create(new InetSocketAddress(8000), 0)
hs.createContext("/hello", handler)
hs.start()
URI uri = URI.create("http://localhost:8000/hello")
HttpURLConnection c = (HttpURLConnection) uri.toURL().openConnection()
c.setRequestMethod("GET")
c.getResponseCode()
new BufferedReader(new InputStreamReader(c.getInputStream())).readLine()
CloseableHttpClient client = HttpClients.createDefault()
HttpGet request = new HttpGet(uri)
CloseableHttpResponse response = client.execute(request)
response.getProtocolVersion()
response.getStatusLine().getStatusCode()
EntityUtils.toString(response.getEntity())
HttpClient client = HttpClient.newHttpClient()
client.version()
HttpRequest request = HttpRequest.newBuilder().uri(uri).GET().build()
HttpResponse<String> response = client.send(request, BodyHandlers.ofString())
response.statusCode()
response.body()
CompletableFuture<HttpResponse<String>> response = client.sendAsync(request, BodyHandlers.ofString())
response.get().body()