Use type expressions from Java 17 (#207)

* Use type expressions from Java 17

* Update jfr-streaming/src/main/java/io/opentelemetry/contrib/jfr/metrics/internal/memory/GCHeapSummaryHandler.java

Co-authored-by: Lauri Tulmin <[email protected]>

Co-authored-by: Lauri Tulmin <[email protected]>

Author: anuraaga

jfr-streaming/src/main/java/io/opentelemetry/contrib/jfr/metrics/internal/ThreadGrouper.java

@@ -13,8 +13,8 @@ public final class ThreadGrouper {
   // FIXME doesn't actually do any grouping, but should be safe for now
   public Optional<String> groupedName(RecordedEvent ev) {
     Object thisField = ev.getValue("eventThread");
-    if (thisField instanceof RecordedThread) {
-      return Optional.of(((RecordedThread) thisField).getJavaName());
+    if (thisField instanceof RecordedThread thread) {
+      return Optional.of(thread.getJavaName());
     }
     return Optional.empty();
   }

jfr-streaming/src/main/java/io/opentelemetry/contrib/jfr/metrics/internal/memory/GCHeapSummaryHandler.java

@@ -105,9 +105,7 @@ private void recordValues(RecordedEvent before, RecordedEvent after) {
       memoryHistogram.record(after.getLong(HEAP_USED), ATTR_MEMORY_USED);
     }
     if (after.hasField(HEAP_SPACE)) {
-      after.getValue(HEAP_SPACE);
-      if (after.getValue(HEAP_SPACE) instanceof RecordedObject) {
-        RecordedObject ro = after.getValue(HEAP_SPACE);
+      if (after.getValue(HEAP_SPACE) instanceof RecordedObject ro) {
         memoryHistogram.record(ro.getLong(COMMITTED_SIZE), ATTR_MEMORY_COMMITTED);
       }
     }