Add test for #1759, passes for now (and fails with trivial forced race condition)

Author: cowtowncoder

src/test/java/com/fasterxml/jackson/databind/misc/RaceCondition738Test.java

@@ -63,7 +63,7 @@ public void testRepeatedly() throws Exception {
     }
 
     void runOnce(int round, int max) throws Exception {
-        final ObjectMapper mapper = getObjectMapper();
+        final ObjectMapper mapper = newObjectMapper();
         Callable<String> writeJson = new Callable<String>() {
             @Override
             public String call() throws Exception {
@@ -92,8 +92,4 @@ public String call() throws Exception {
             }
         }
     }
-
-    private static ObjectMapper getObjectMapper() {
-        return new ObjectMapper();
-    }
 }

src/test/java/com/fasterxml/jackson/databind/misc/ThreadSafety1759Test.java

@@ -0,0 +1,71 @@
+package com.fasterxml.jackson.databind.misc;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Date;
+import java.util.List;
+import java.util.concurrent.*;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import com.fasterxml.jackson.databind.*;
+
+public class ThreadSafety1759Test extends BaseMapTest
+{
+    /*
+    /**********************************************************
+    /* Test methods
+    /**********************************************************
+     */
+
+    public void testCalendarForDeser() throws Exception
+    {
+        final ObjectMapper mapper = newObjectMapper();
+
+        final int numThreads = 4;
+        final int COUNT = 3000;
+        final AtomicInteger counter = new AtomicInteger();
+
+        // IMPORTANT! Use different timestamp for every thread
+        List<Callable<Throwable>> calls = new ArrayList<Callable<Throwable>>();
+        for (int thread = 1; thread <= numThreads; ++thread) {
+            final String json = quote(String.format("2017-01-%02dT16:30:49Z", thread));
+            final long timestamp = mapper.readValue(json, Date.class).getTime();
+
+            calls.add(createCallable(thread, mapper, json, timestamp, COUNT, counter));
+        }
+
+        ExecutorService executor = Executors.newFixedThreadPool(numThreads);
+        List<Future<Throwable>> results = new ArrayList<>();
+        for (Callable<Throwable> c : calls) {
+            results.add(executor.submit(c));
+        }
+        executor.shutdown();
+        for (Future<Throwable> f : results) {
+            Throwable t = f.get(5, TimeUnit.SECONDS);
+            if (t != null) {
+                fail("Exception during processing: "+t.getMessage());
+            }
+        }
+        assertEquals(numThreads * COUNT, counter.get());
+    }
+
+    private Callable<Throwable> createCallable(final int threadId,
+            final ObjectMapper mapper,
+            final String json, final long timestamp,
+            final int count, final AtomicInteger counter)
+    {
+        return new Callable<Throwable>() {
+            @Override
+            public Throwable call() throws IOException {
+                for (int i = 0; i < count; ++i) {
+                    Date dt = mapper.readValue(json, Date.class);
+                    if (dt.getTime() != timestamp) {
+                        return new IllegalArgumentException("Wrong timestamp (thread id "+threadId+", input: "+json+": should get "+timestamp+", got "+dt.getTime());
+                    }
+                    counter.addAndGet(1);
+                }
+                return null;
+            }
+        };
+    }
+}