8370905: Update vm.defmeth tests to use virtual threads

test/hotspot/jtreg/vmTestbase/vm/runtime/defmeth/StressTest.java

@@ -44,6 +44,7 @@
 import java.util.List;
 import java.util.Random;
 
+import jdk.test.lib.thread.TestThreadFactory;
 import nsk.share.TestFailure;
 import nsk.share.test.StressOptions;
 import nsk.share.test.Stresser;
@@ -82,16 +83,19 @@ public class StressTest implements Runnable {
  @Option(name="ignoreTestFailures", default_value="false", description="ignore failures of the executed tests")
  private boolean ignoreTestFailures;
 
- class Worker extends Thread {
+ class Worker implements Runnable {
  private final Random rand;
 
  private volatile DefMethTest failedTest;
  private Throwable reason;
  private volatile long executedTests = 0;
 
- public Worker(String id, long seed) {
- setName(id);
- this.rand = new Random(seed);
+ private final Thread thread;
+
+ Worker(String id, long seed) {
+ this.rand = new Random(seed);
+ this.thread = TestThreadFactory.newThread(this, id);
+ thread.setName(id);
  }
 
  @Override
@@ -247,28 +251,28 @@ private void startWorkers() {
  }
 
  for (Worker worker : workers) {
- worker.start();
+ worker.thread.start();
  }
  }
 
  private void interruptWorkers() {
  for (Worker worker : workers) {
- worker.interrupt();
+ worker.thread.interrupt();
  }
  }
 
  private void joinWorkers() {
  boolean isFailed = false;
 
  for (Worker worker : workers) {
- while (worker.isAlive()) {
+ while (worker.thread.isAlive()) {
  try {
- worker.join();
+ worker.thread.join();
  } catch (InterruptedException e) {}
  }
 
  System.out.printf("%s: %s (executed: %d)\n",
- worker.getName(),
+ worker.thread.getName(),
  worker.isFailed() ? "FAILED: " + worker.getFailedTest() : "PASSED",
  worker.getExecutedTests());
 
@@ -288,7 +292,7 @@ private void joinWorkers() {
 
  private boolean workersAlive() {
  for (Worker worker : workers) {
- if (!worker.isAlive()) {
+ if (!worker.thread.isAlive()) {
  return false;
  }
  }