hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestRegionInfoStaticInitialization.java

   1 /*
   2  * Licensed to the Apache Software Foundation (ASF) under one
   3  * or more contributor license agreements.  See the NOTICE file
   4  * distributed with this work for additional information
   5  * regarding copyright ownership.  The ASF licenses this file
   6  * to you under the Apache License, Version 2.0 (the
   7  * "License"); you may not use this file except in compliance
   8  * with the License.  You may obtain a copy of the License at
   9  *
  10  *     http://www.apache.org/licenses/LICENSE-2.0
  11  *
  12  * Unless required by applicable law or agreed to in writing, software
  13  * distributed under the License is distributed on an "AS IS" BASIS,
  14  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  15  * See the License for the specific language governing permissions and
  16  * limitations under the License.
  17  */
  18 package org.apache.hadoop.hbase.regionserver;
  19
  20 import java.util.concurrent.CompletableFuture;
  21 import java.util.concurrent.TimeUnit;
  22 import java.util.function.Supplier;
  23 import java.util.stream.Stream;
  24 import org.apache.hadoop.hbase.HBaseClassTestRule;
  25 import org.apache.hadoop.hbase.client.RegionInfo;
  26 import org.apache.hadoop.hbase.client.RegionInfoBuilder;
  27 import org.apache.hadoop.hbase.testclassification.LargeTests;
  28 import org.apache.hadoop.hbase.testclassification.RegionServerTests;
  29 import org.junit.ClassRule;
  30 import org.junit.Test;
  31 import org.junit.experimental.categories.Category;
  32
  33 /**
  34  * Test for the tangled mess that is static initialization of our our {@link RegionInfo} and
  35  * {@link RegionInfoBuilder}, as reported on HBASE-24896. The condition being tested can only be
  36  * reproduced the first time a JVM loads the classes under test. Thus, this test is marked as a
  37  * {@link LargeTests} because, under their current configuration, tests in that category are run
  38  * in their own JVM instances.
  39  */
  40 @SuppressWarnings("deprecation")
  41 @Category({ RegionServerTests.class, LargeTests.class})
  42 public class TestRegionInfoStaticInitialization {
  43   @ClassRule
  44   public static final HBaseClassTestRule CLASS_RULE =
  45     HBaseClassTestRule.forClass(TestRegionInfoStaticInitialization.class);
  46
  47   @Test
  48   public void testParallelStaticInitialization() throws Exception {
  49     // The JVM loads symbols lazily. These suppliers reference two symbols that, before this patch,
  50     // are mutually dependent and expose a deadlock in the loading of symbols from RegionInfo and
  51     // RegionInfoBuilder.
  52     final Supplier<RegionInfo> retrieveUNDEFINED = () -> RegionInfo.UNDEFINED;
  53     final Supplier<RegionInfo> retrieveMetaRegionInfo =
  54       () -> RegionInfoBuilder.FIRST_META_REGIONINFO;
  55
  56     // The test runs multiple threads that reference these mutually dependent symbols. In order to
  57     // express this bug, these threads need to access these symbols at roughly the same time, so
  58     // that the classloader is asked to materialize these symbols concurrently. These Suppliers are
  59     // run on threads that have already been allocated, managed by the system's ForkJoin pool.
  60     final CompletableFuture<?>[] futures = Stream.of(
  61       retrieveUNDEFINED, retrieveMetaRegionInfo, retrieveUNDEFINED, retrieveMetaRegionInfo)
  62       .map(CompletableFuture::supplyAsync)
  63       .toArray(CompletableFuture<?>[]::new);
  64
  65     // Loading classes should be relatively fast. 5 seconds is an arbitrary choice of timeout. It
  66     // was chosen under the assumption that loading these symbols should complete much faster than
  67     // this window.
  68     CompletableFuture.allOf(futures).get(5, TimeUnit.SECONDS);
  69   }
  70 }