Merge pull request ronmamo#206 from andreabertagnolli/issue81

Fix issue ronmamo#81 by disabling cache's use on url connection

src/main/java/org/reflections/vfs/Vfs.java

@@ -9,12 +9,14 @@
 import org.reflections.util.Utils;
 
 import javax.annotation.Nullable;
-import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.UnsupportedEncodingException;
 import java.net.*;
-import java.util.*;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Iterator;
+import java.util.List;
 import java.util.jar.JarFile;
 
 /**
@@ -226,7 +228,8 @@ public Dir createDir(URL url) throws Exception {
                 try {
                     URLConnection urlConnection = url.openConnection();
                     if (urlConnection instanceof JarURLConnection) {
-                            return new ZipDir(((JarURLConnection) urlConnection).getJarFile());
+                        urlConnection.setUseCaches(false);
+                        return new ZipDir(((JarURLConnection) urlConnection).getJarFile());
                     }
                 } catch (Throwable e) { /*fallback*/ }
                 java.io.File file = getFile(url);

src/test/java/org/reflections/ReflectionsThreadSafenessTest.java

@@ -0,0 +1,45 @@
+package org.reflections;
+
+import com.google.common.collect.ImmutableMap;
+import org.junit.Test;
+import org.reflections.scanners.SubTypesScanner;
+import org.reflections.util.ClasspathHelper;
+import org.reflections.util.ConfigurationBuilder;
+
+import java.util.Set;
+import java.util.concurrent.Callable;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+
+import static java.util.Collections.singletonList;
+import static java.util.concurrent.TimeUnit.SECONDS;
+import static org.junit.Assert.assertEquals;
+
+public class ReflectionsThreadSafenessTest {
+
+    /**
+     * https://github.com/ronmamo/reflections/issues/81
+     */
+    @Test
+    public void reflections_scan_is_thread_safe() throws Exception {
+
+        Callable<Set<Class<? extends ImmutableMap>>> callable = new Callable<Set<Class<? extends ImmutableMap>>>() {
+            @Override
+            public Set<Class<? extends ImmutableMap>> call() throws Exception {
+                final Reflections reflections = new Reflections(new ConfigurationBuilder()
+                        .setUrls(singletonList(ClasspathHelper.forClass(ImmutableMap.class)))
+                        .setScanners(new SubTypesScanner(false)));
+
+                return reflections.getSubTypesOf(ImmutableMap.class);
+            }
+        };
+
+        final ExecutorService pool = Executors.newFixedThreadPool(2);
+
+        final Future<?> first = pool.submit(callable);
+        final Future<?> second = pool.submit(callable);
+
+        assertEquals(first.get(5, SECONDS), second.get(5, SECONDS));
+    }
+}