Add stress test for Java worker

java/runtime/src/main/java/org/ray/runtime/AbstractRayRuntime.java

@@ -75,7 +75,7 @@ public <T> RayObject<T> put(T obj) {
 
   public <T> void put(UniqueId objectId, T obj) {
     UniqueId taskId = workerContext.getCurrentTask().taskId;
-    RayLog.core.info("Putting object {}, for task {} ", objectId, taskId);
+    RayLog.core.debug("Putting object {}, for task {} ", objectId, taskId);
     objectStoreProxy.put(objectId, obj, null);
   }
 

java/runtime/src/main/java/org/ray/runtime/raylet/RayletClientImpl.java

@@ -90,8 +90,8 @@ public TaskSpec getTask() {
   @Override
   public void fetchOrReconstruct(List<UniqueId> objectIds, boolean fetchOnly,
       UniqueId currentTaskId) {
-    if (RayLog.core.isInfoEnabled()) {
-      RayLog.core.info("Blocked on objects for task {}, object IDs are {}",
+    if (RayLog.core.isDebugEnabled()) {
+      RayLog.core.debug("Blocked on objects for task {}, object IDs are {}",
           UniqueIdUtil.computeTaskId(objectIds.get(0)), objectIds);
     }
     nativeFetchOrReconstruct(client, UniqueIdUtil.getIdBytes(objectIds),

java/test/src/main/java/org/ray/api/test/StressTest.java

@@ -0,0 +1,98 @@
+package org.ray.api.test;
+
+import com.google.common.collect.ImmutableList;
+import java.util.ArrayList;
+import java.util.List;
+import org.junit.Assert;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.ray.api.Ray;
+import org.ray.api.RayActor;
+import org.ray.api.RayObject;
+import org.ray.api.id.UniqueId;
+
+@RunWith(MyRunner.class)
+public class StressTest {
+
+  public static int echo(int x) {
+    return x;
+  }
+
+  @Test
+  public void testSubmittingTasks() {
+    for (int numIterations : ImmutableList.of(1, 10, 100, 1000)) {
+      int numTasks = 1000 / numIterations;
+      for (int i = 0; i < numIterations; i++) {
+        List<UniqueId> resultIds = new ArrayList<>();
+        for (int j = 0; j < numTasks; j++) {
+          resultIds.add(Ray.call(StressTest::echo, 1).getId());
+        }
+        for (Integer result : Ray.<Integer>get(resultIds)) {
+          Assert.assertEquals(result, Integer.valueOf(1));
+        }
+      }
+    }
+  }
+
+  @Test
+  public void testDependency() {
+    RayObject<Integer> x = Ray.call(StressTest::echo, 1);
+    for (int i = 0; i < 1000; i++) {
+      x = Ray.call(StressTest::echo, x);
+    }
+    Assert.assertEquals(x.get(), Integer.valueOf(1));
+  }
+
+  public static class Actor {
+
+    public int ping() {
+      return 1;
+    }
+  }
+
+  public static class Worker {
+
+    private RayActor<Actor> actor;
+
+    public Worker(RayActor<Actor> actor) {
+      this.actor = actor;
+    }
+
+    public int ping(int n) {
+      List<UniqueId> objectIds = new ArrayList<>();
+      for (int i = 0; i < n; i++) {
+        objectIds.add(Ray.call(Actor::ping, actor).getId());
+      }
+      int sum = 0;
+      for (Integer result : Ray.<Integer>get(objectIds)) {
+        sum += result;
+      }
+      return sum;
+    }
+  }
+
+  @Test
+  public void testSubmittingManyTasksToOneActor() {
+    RayActor<Actor> actor = Ray.createActor(Actor::new);
+    List<UniqueId> objectIds = new ArrayList<>();
+    for (int i = 0; i < 10; i++) {
+      RayActor<Worker> worker = Ray.createActor(Worker::new, actor);
+      objectIds.add(Ray.call(Worker::ping, worker, 100).getId());
+    }
+    for (Integer result : Ray.<Integer>get(objectIds)) {
+      Assert.assertEquals(result, Integer.valueOf(100));
+    }
+  }
+
+  @Test
+  public void testPuttingAndGettingManyObjects() {
+    Integer objectToPut = 1;
+    List<RayObject<Integer>> objects = new ArrayList<>();
+    for (int i = 0; i < 100_000; i++) {
+      objects.add(Ray.put(objectToPut));
+    }
+    for (RayObject<Integer> object : objects) {
+      Assert.assertEquals(object.get(), objectToPut);
+    }
+  }
+}