Fix eager classes

core/deployment/src/main/java/io/quarkus/runner/bootstrap/StartupActionImpl.java

@@ -15,6 +15,8 @@
 import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.function.Consumer;
 
@@ -80,6 +82,42 @@ public StartupActionImpl(CuratedApplication curatedApplication, BuildResult buil
                     resources, transformedClasses);
         }
         this.runtimeClassLoader = runtimeClassLoader;
+        handleEagerClasses(runtimeClassLoader, eagerClasses);
+    }
+
+
+    private void handleEagerClasses(QuarkusClassLoader runtimeClassLoader, Set<String> eagerClasses) {
+        int availableProcessors = Runtime.getRuntime().availableProcessors();
+        if (availableProcessors == 1) {
+            return;
+        }
+        //leave one processor for the main startup thread
+        ExecutorService loadingExecutor = Executors.newFixedThreadPool(availableProcessors - 1);
+        for (String i : eagerClasses) {
+            loadingExecutor.submit(new Runnable() {
+                @Override
+                public void run() {
+                    try {
+                        //no need to restore the old TCCL, this thread is going away
+                        Thread.currentThread().setContextClassLoader(runtimeClassLoader);
+                        runtimeClassLoader.loadClass(i);
+                    } catch (ClassNotFoundException e) {
+                        log.debug("Failed to eagerly load class", e);
+                        //we just ignore this for now, the problem
+                        //will be reported for real in the startup sequence
+                    }
+                }
+            });
+        }
+        Thread t = new Thread(new Runnable() {
+            @Override
+            public void run() {
+                //when all the jobs are done we shut down
+                //we do this in a new thread to allow the main thread to continue doing startup
+                loadingExecutor.shutdown();
+            }
+        });
+        t.start();
     }
 
     /**