8268056: Update java.net and java.nio to use switch expressions

Reviewed-by: dfuchs, michaelm, chegar, iris, alanb

Author: pconcannon

src/java.base/share/classes/java/net/SocksSocketImpl.java

@@ -211,25 +211,17 @@ private void connectV4(InputStream in, OutputStream out,
             throw new SocketException("Reply from SOCKS server has bad length: " + n);
         if (data[0] != 0 && data[0] != 4)
             throw new SocketException("Reply from SOCKS server has bad version");
-        SocketException ex = null;
-        switch (data[1]) {
-        case 90:
-            // Success!
-            external_address = endpoint;
-            break;
-        case 91:
-            ex = new SocketException("SOCKS request rejected");
-            break;
-        case 92:
-            ex = new SocketException("SOCKS server couldn't reach destination");
-            break;
-        case 93:
-            ex = new SocketException("SOCKS authentication failed");
-            break;
-        default:
-            ex = new SocketException("Reply from SOCKS server contains bad status");
-            break;
-        }
+        SocketException ex = switch (data[1]) {
+            case 90 -> {
+                // Success!
+                external_address = endpoint;
+                yield null;
+            }
+            case 91 -> new SocketException("SOCKS request rejected");
+            case 92 -> new SocketException("SOCKS server couldn't reach destination");
+            case 93 -> new SocketException("SOCKS authentication failed");
+            default -> new SocketException("Reply from SOCKS server contains bad status");
+        };
         if (ex != null) {
             in.close();
             out.close();

src/java.base/share/classes/java/nio/file/Files.java

@@ -2803,40 +2803,37 @@ public static Path walkFileTree(Path start,
         try (FileTreeWalker walker = new FileTreeWalker(options, maxDepth)) {
             FileTreeWalker.Event ev = walker.walk(start);
             do {
-                FileVisitResult result;
-                switch (ev.type()) {
-                    case ENTRY :
+                FileVisitResult result = switch (ev.type()) {
+                    case ENTRY -> {
                         IOException ioe = ev.ioeException();
                         if (ioe == null) {
                             assert ev.attributes() != null;
-                            result = visitor.visitFile(ev.file(), ev.attributes());
+                            yield visitor.visitFile(ev.file(), ev.attributes());
                         } else {
-                            result = visitor.visitFileFailed(ev.file(), ioe);
+                            yield visitor.visitFileFailed(ev.file(), ioe);
                         }
-                        break;
-
-                    case START_DIRECTORY :
-                        result = visitor.preVisitDirectory(ev.file(), ev.attributes());
+                    }
+                    case START_DIRECTORY -> {
+                        var res = visitor.preVisitDirectory(ev.file(), ev.attributes());
 
                         // if SKIP_SIBLINGS and SKIP_SUBTREE is returned then
                         // there shouldn't be any more events for the current
                         // directory.
-                        if (result == FileVisitResult.SKIP_SUBTREE ||
-                            result == FileVisitResult.SKIP_SIBLINGS)
+                        if (res == FileVisitResult.SKIP_SUBTREE ||
+                            res == FileVisitResult.SKIP_SIBLINGS)
                             walker.pop();
-                        break;
-
-                    case END_DIRECTORY :
-                        result = visitor.postVisitDirectory(ev.file(), ev.ioeException());
+                        yield res;
+                    }
+                    case END_DIRECTORY -> {
+                        var res = visitor.postVisitDirectory(ev.file(), ev.ioeException());
 
                         // SKIP_SIBLINGS is a no-op for postVisitDirectory
-                        if (result == FileVisitResult.SKIP_SIBLINGS)
-                            result = FileVisitResult.CONTINUE;
-                        break;
-
-                    default :
-                        throw new AssertionError("Should not get here");
-                }
+                        if (res == FileVisitResult.SKIP_SIBLINGS)
+                            res = FileVisitResult.CONTINUE;
+                        yield res;
+                    }
+                    default -> throw new AssertionError("Should not get here");
+                };
 
                 if (Objects.requireNonNull(result) != FileVisitResult.CONTINUE) {
                     if (result == FileVisitResult.TERMINATE) {