今天在测试phoenix的二级索引功能时，创建完索引写入数据，出现以下异常：

Caused by: org.apache.hadoop.hbase.client.RetriesExhaustedWithDetailsException: Failed 1 action: org.apache.phoenix.hbase.index.builder.IndexBuildingFailureException: Failed to build index for unexpected reason!
        at org.apache.phoenix.hbase.index.util.IndexManagementUtil.rethrowIndexingException(IndexManagementUtil.java:206)
        at org.apache.phoenix.hbase.index.Indexer.preBatchMutate(Indexer.java:351)
        at org.apache.hadoop.hbase.regionserver.RegionCoprocessorHost$28.call(RegionCoprocessorHost.java:1010)
        at org.apache.hadoop.hbase.regionserver.RegionCoprocessorHost$28.call(RegionCoprocessorHost.java:1007)
        at org.apache.hadoop.hbase.coprocessor.CoprocessorHost$ObserverOperationWithoutResult.callObserver(CoprocessorHost.java:540)
        at org.apache.hadoop.hbase.coprocessor.CoprocessorHost.execOperation(CoprocessorHost.java:614)
        at org.apache.hadoop.hbase.regionserver.RegionCoprocessorHost.preBatchMutate(RegionCoprocessorHost.java:1007)
        at org.apache.hadoop.hbase.regionserver.HRegion$MutationBatchOperation.prepareMiniBatchOperations(HRegion.java:3487)
        at org.apache.hadoop.hbase.regionserver.HRegion.doMiniBatchMutate(HRegion.java:3896)
        at org.apache.hadoop.hbase.regionserver.HRegion.batchMutate(HRegion.java:3854)
        at org.apache.hadoop.hbase.regionserver.HRegion.batchMutate(HRegion.java:3785)
        at org.apache.hadoop.hbase.regionserver.RSRpcServices.doBatchOp(RSRpcServices.java:908)
        at org.apache.hadoop.hbase.regionserver.RSRpcServices.doNonAtomicBatchOp(RSRpcServices.java:836)
        at org.apache.hadoop.hbase.regionserver.RSRpcServices.doNonAtomicRegionMutation(RSRpcServices.java:799)
        at org.apache.hadoop.hbase.regionserver.RSRpcServices.multi(RSRpcServices.java:2551)
        at org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos$ClientService$2.callBlockingMethod(ClientProtos.java:42014)
        at org.apache.hadoop.hbase.ipc.RpcServer.call(RpcServer.java:413)
        at org.apache.hadoop.hbase.ipc.CallRunner.run(CallRunner.java:130)
        at org.apache.hadoop.hbase.ipc.RpcExecutor$Handler.run(RpcExecutor.java:324)
        at org.apache.hadoop.hbase.ipc.RpcExecutor$Handler.run(RpcExecutor.java:304)
Caused by: java.lang.VerifyError: class org.apache.phoenix.hbase.index.covered.data.IndexMemStore$1 overrides final method compare.(Lorg/apache/hadoop/hbase/Cell;Lorg/apache/hadoop/hbase/Cell;)I
        at java.lang.ClassLoader.defineClass1(Native Method)
        at java.lang.ClassLoader.defineClass(ClassLoader.java:763)
        at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
        at java.net.URLClassLoader.defineClass(URLClassLoader.java:467)
        at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:368)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:362)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:361)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:335)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
        at org.apache.phoenix.hbase.index.covered.data.IndexMemStore.<init>(IndexMemStore.java:82)
        at org.apache.phoenix.hbase.index.covered.LocalTableState.<init>(LocalTableState.java:57)
        at org.apache.phoenix.hbase.index.covered.NonTxIndexBuilder.getIndexUpdate(NonTxIndexBuilder.java:52)
        at org.apache.phoenix.hbase.index.builder.IndexBuildManager.getIndexUpdate(IndexBuildManager.java:90)
        at org.apache.phoenix.hbase.index.Indexer.preBatchMutateWithExceptions(Indexer.java:503)
        at org.apache.phoenix.hbase.index.Indexer.preBatchMutate(Indexer.java:348)

异常信息可以看出是IndexMemStore这个类初始化的时候加载class时碰到了VerifyError，具体来说就是试图覆盖1个被标记为final的方法，先找这个类的代码看看：

public class IndexMemStore implements KeyValueStore {

  private static final Log LOG = LogFactory.getLog(IndexMemStore.class);
  private IndexKeyValueSkipListSet kvset;
  private CellComparator comparator;

  public IndexMemStore() {
    this(new CellComparatorImpl(){
        @Override
        public int compare(Cell a, Cell b) {
            return super.compare(a, b, true);
        }
    });
  }

覆盖的是CellComparatorImpl的compare方法，该类在hbase-common模块中，我们用的phoenix版本是5.0.0，对应的hbase版本为2.0.0，找到代码看看：

  @Override
  public int compare(Cell a, Cell b) {
    return compare(a, b, false);
  }

可以看到这个方法并非final，我们使用的是CDH6.0.1，对应的hbase也是2.0.0版本，莫非有所不同，找到代码看看：

  @Override
  public final int compare(final Cell a, final Cell b) {
    return compare(a, b, false);
  }

居然真的有final修饰符，于是查看社区中该类的修改历史，发现是在2.0.1中进行的如上改动，对应的jira：HBASE-20620，可以看到改动记录：

@@ -57,21 +64,17 @@ public class CellComparatorImpl implements CellComparator {
   public static final CellComparatorImpl META_COMPARATOR = new MetaCellComparator();
 
   @Override
-  public int compare(Cell a, Cell b) {
+  public final int compare(final Cell a, final Cell b) {
     return compare(a, b, false);
   }

看起来应该是CDH6.0.1中包含了某些hbase2.0.0之后的patch；

解决方法就是修改hbase，把final修饰符去掉即可，然后打包、停服务、换包、起服务，再试已经正常；