Package org.apache.hadoop.hbase.client

package org.apache.hadoop.hbase.client

Provides HBase Client

Table of Contents

• Overview
• Example API Usage

Overview

To administer HBase, create and drop tables, list and alter tables, use Admin. Once created, table access is via an instance of Table. You add content to a table a row at a time. To insert, create an instance of a Put object. Specify value, target column and optionally a timestamp. Commit your update using Table.put(Put). To fetch your inserted value, use Get. The Get can be specified to be broad -- get all on a particular row -- or narrow; i.e. return only a single cell value. After creating an instance of Get, invoke Table.get(Get).

Use Scan to set up a scanner -- a Cursor- like access. After creating and configuring your Scan instance, call Table.getScanner(Scan) and then invoke next on the returned object. Both Table.get(Get) and Table.getScanner(Scan) return a Result.

Use Delete to remove content. You can remove individual cells or entire families, etc. Pass it to Table.delete(Delete) to execute.

Puts, Gets and Deletes take out a lock on the target row for the duration of their operation. Concurrent modifications to a single row are serialized. Gets and scans run concurrently without interference of the row locks and are guaranteed to not to return half written rows.

Client code accessing a cluster finds the cluster by querying ZooKeeper. This means that the ZooKeeper quorum to use must be on the client CLASSPATH. Usually this means make sure the client can find your hbase-site.xml.

Example API Usage

Once you have a running HBase, you probably want a way to hook your application up to it. If your application is in Java, then you should use the Java API. Here's an example of what a simple client might look like. This example assumes that you've created a table called "myTable" with a column family called "myColumnFamily".

import java.io.IOException;

import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.Connection;
import org.apache.hadoop.hbase.client.ConnectionFactory;
import org.apache.hadoop.hbase.client.Get;
import org.apache.hadoop.hbase.client.Table;
import org.apache.hadoop.hbase.client.Put;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.client.ResultScanner;
import org.apache.hadoop.hbase.client.Scan;
import org.apache.hadoop.hbase.util.Bytes;

// Class that has nothing but a main.
// Does a Put, Get and a Scan against an hbase table.
// The API described here is since HBase 1.0.
public class MyLittleHBaseClient {
  public static void main(String[] args) throws IOException {
    // You need a configuration object to tell the client where to connect.
    // When you create a HBaseConfiguration, it reads in whatever you've set
    // into your hbase-site.xml and in hbase-default.xml, as long as these can
    // be found on the CLASSPATH
    Configuration config = HBaseConfiguration.create();

    // Next you need a Connection to the cluster. Create one. When done with it,
    // close it. A try/finally is a good way to ensure it gets closed or use
    // the jdk7 idiom, try-with-resources: see
    // https://docs.oracle.com/javase/tutorial/essential/exceptions/tryResourceClose.html
    //
    // Connections are heavyweight.  Create one once and keep it around. From a Connection
    // you get a Table instance to access Tables, an Admin instance to administer the cluster,
    // and RegionLocator to find where regions are out on the cluster. As opposed to Connections,
    // Table, Admin and RegionLocator instances are lightweight; create as you need them and then
    // close when done.
    //
    Connection connection = ConnectionFactory.createConnection(config);
    try {

      // The below instantiates a Table object that connects you to the "myLittleHBaseTable" table
      // (TableName.valueOf turns String into a TableName instance).
      // When done with it, close it (Should start a try/finally after this creation so it gets
      // closed for sure the jdk7 idiom, try-with-resources: see
      // https://docs.oracle.com/javase/tutorial/essential/exceptions/tryResourceClose.html)
      Table table = connection.getTable(TableName.valueOf("myLittleHBaseTable"));
      try {

        // To add to a row, use Put.  A Put constructor takes the name of the row
        // you want to insert into as a byte array.  In HBase, the Bytes class has
        // utility for converting all kinds of java types to byte arrays.  In the
        // below, we are converting the String "myLittleRow" into a byte array to
        // use as a row key for our update. Once you have a Put instance, you can
        // adorn it by setting the names of columns you want to update on the row,
        // the timestamp to use in your update, etc. If no timestamp, the server
        // applies current time to the edits.
        Put p = new Put(Bytes.toBytes("myLittleRow"));

        // To set the value you'd like to update in the row 'myLittleRow', specify
        // the column family, column qualifier, and value of the table cell you'd
        // like to update.  The column family must already exist in your table
        // schema.  The qualifier can be anything.  All must be specified as byte
        // arrays as hbase is all about byte arrays.  Lets pretend the table
        // 'myLittleHBaseTable' was created with a family 'myLittleFamily'.
        p.add(Bytes.toBytes("myLittleFamily"), Bytes.toBytes("someQualifier"),
        Bytes.toBytes("Some Value"));

        // Once you've adorned your Put instance with all the updates you want to
        // make, to commit it do the following (The HTable#put method takes the
        // Put instance you've been building and pushes the changes you made into
        // hbase)
        table.put(p);

        // Now, to retrieve the data we just wrote. The values that come back are
        // Result instances. Generally, a Result is an object that will package up
        // the hbase return into the form you find most palatable.
        Get g = new Get(Bytes.toBytes("myLittleRow"));
        Result r = table.get(g);
        byte [] value = r.getValue(Bytes.toBytes("myLittleFamily"),
          Bytes.toBytes("someQualifier"));

        // If we convert the value bytes, we should get back 'Some Value', the
        // value we inserted at this location.
        String valueStr = Bytes.toString(value);
        System.out.println("GET: " + valueStr);

        // Sometimes, you won't know the row you're looking for. In this case, you
        // use a Scanner. This will give you cursor-like interface to the contents
        // of the table.  To set up a Scanner, do like you did above making a Put
        // and a Get, create a Scan.  Adorn it with column names, etc.
        Scan s = new Scan();
        s.addColumn(Bytes.toBytes("myLittleFamily"), Bytes.toBytes("someQualifier"));
        ResultScanner scanner = table.getScanner(s);
        try {
           // Scanners return Result instances.
           // Now, for the actual iteration. One way is to use a while loop like so:
           for (Result rr = scanner.next(); rr != null; rr = scanner.next()) {
             // print out the row we found and the columns we were looking for
             System.out.println("Found row: " + rr);
           }

           // The other approach is to use a foreach loop. Scanners are iterable!
           // for (Result rr : scanner) {
           //   System.out.println("Found row: " + rr);
           // }
         } finally {
           // Make sure you close your scanners when you are done!
           // Thats why we have it inside a try/finally clause
           scanner.close();
         }

         // Close your table and cluster connection.
       } finally {
         if (table != null) table.close();
       }
     } finally {
       connection.close();
     }
  }
}

There are many other methods for putting data into and getting data out of HBase, but these examples should get you started. See the Table javadoc for more methods. Additionally, there are methods for managing tables in the Admin class.

If your client is NOT Java, then you should consider the Thrift or REST libraries.

Related Documentation

• HBase Home Page
• Hadoop Home Page

See also the section in the HBase Reference Guide where it discusses HBase Client. It has section on how to access HBase from inside your multithreaded environment how to control resources consumed client-side, etc.

Related Packages

Package	Description
org.apache.hadoop.hbase
org.apache.hadoop.hbase.client.backoff
org.apache.hadoop.hbase.client.example
org.apache.hadoop.hbase.client.locking
org.apache.hadoop.hbase.client.replication
org.apache.hadoop.hbase.client.security
org.apache.hadoop.hbase.client.trace

Class	Description
org.apache.hadoop.hbase.client.AbstractClientScanner	Helper class for custom client scanners.
org.apache.hadoop.hbase.client.Action	A Get, Put, Increment, Append, or Delete associated with it's region.
org.apache.hadoop.hbase.client.Admin	The administrative API for HBase.
org.apache.hadoop.hbase.client.AdvancedScanResultConsumer	This is the low level API for asynchronous scan.
org.apache.hadoop.hbase.client.AdvancedScanResultConsumer.ScanController	Used to suspend or stop a scan, or get a scan cursor if available.
org.apache.hadoop.hbase.client.AdvancedScanResultConsumer.ScanResumer	Used to resume a scan.
org.apache.hadoop.hbase.client.Append	Performs Append operations on a single row.
org.apache.hadoop.hbase.client.AsyncAdmin	The asynchronous administrative API for HBase.
org.apache.hadoop.hbase.client.AsyncAdminBuilder	For creating AsyncAdmin.
org.apache.hadoop.hbase.client.AsyncAdminClientUtils	Additional Asynchronous Admin capabilities for clients.
org.apache.hadoop.hbase.client.AsyncAdminRequestRetryingCaller<T>
org.apache.hadoop.hbase.client.AsyncAdminRequestRetryingCaller.Callable<T>
org.apache.hadoop.hbase.client.AsyncBufferedMutator	Used to communicate with a single HBase table in batches.
org.apache.hadoop.hbase.client.AsyncBufferedMutatorBuilder	For creating AsyncBufferedMutator.
org.apache.hadoop.hbase.client.AsyncConnection	The asynchronous version of Connection.
org.apache.hadoop.hbase.client.AsyncConnectionImpl	The implementation of AsyncConnection.
org.apache.hadoop.hbase.client.AsyncMasterRequestRpcRetryingCaller<T>	Retry caller for a request call to master.
org.apache.hadoop.hbase.client.AsyncMasterRequestRpcRetryingCaller.Callable<T>
org.apache.hadoop.hbase.client.AsyncProcessTask<T>	Contains the attributes of a task which will be executed by AsyncProcess.
org.apache.hadoop.hbase.client.AsyncProcessTask.Builder<T>
org.apache.hadoop.hbase.client.AsyncProcessTask.SubmittedRows	The number of processed rows.
org.apache.hadoop.hbase.client.AsyncRequestFuture	The context used to wait for results from one submit call.
org.apache.hadoop.hbase.client.AsyncRpcRetryingCaller<T>
org.apache.hadoop.hbase.client.AsyncServerRequestRpcRetryingCaller<T>	Retry caller for a request call to region server.
org.apache.hadoop.hbase.client.AsyncServerRequestRpcRetryingCaller.Callable<T>
org.apache.hadoop.hbase.client.AsyncTable<C extends org.apache.hadoop.hbase.client.ScanResultConsumerBase>	The interface for asynchronous version of Table.
org.apache.hadoop.hbase.client.AsyncTable.CheckAndMutateBuilder	Deprecated. Since 2.4.0, will be removed in 4.0.0.
org.apache.hadoop.hbase.client.AsyncTable.CheckAndMutateWithFilterBuilder	Deprecated. Since 2.4.0, will be removed in 4.0.0.
org.apache.hadoop.hbase.client.AsyncTable.CoprocessorCallback<R>	The callback when we want to execute a coprocessor call on a range of regions.
org.apache.hadoop.hbase.client.AsyncTable.CoprocessorServiceBuilder<S,R>	Helper class for sending coprocessorService request that executes a coprocessor call on regions which are covered by a range.
org.apache.hadoop.hbase.client.AsyncTableBuilder<C extends org.apache.hadoop.hbase.client.ScanResultConsumerBase>	For creating AsyncTable.
org.apache.hadoop.hbase.client.AsyncTableRegionLocator	The asynchronous version of RegionLocator.
org.apache.hadoop.hbase.client.Attributes
BalancerDecision	History of balancer decisions taken for region movements.
org.apache.hadoop.hbase.client.BalancerDecision.Builder
org.apache.hadoop.hbase.client.BalanceRequest	Encapsulates options for executing a run of the Balancer.
org.apache.hadoop.hbase.client.BalanceRequest.Builder	Builder for constructing a BalanceRequest
org.apache.hadoop.hbase.client.BalanceResponse	Response returned from a balancer invocation
org.apache.hadoop.hbase.client.BalanceResponse.Builder	Used in HMaster to build a BalanceResponse for returning results of a balance invocation to callers
BalancerRejection	History of detail information that balancer movements was rejected
org.apache.hadoop.hbase.client.BalancerRejection.Builder
org.apache.hadoop.hbase.client.BatchScanResultCache	A scan result cache for batched scan, i.e, scan.getBatch() > 0 && !scan.getAllowPartialResults().
org.apache.hadoop.hbase.client.BufferedMutator	Used to communicate with a single HBase table similar to Table but meant for batched, asynchronous puts.
org.apache.hadoop.hbase.client.BufferedMutator.ExceptionListener	Listens for asynchronous exceptions on a BufferedMutator.
org.apache.hadoop.hbase.client.BufferedMutatorImpl	Used to communicate with a single HBase table similar to Table but meant for batched, potentially asynchronous puts.
org.apache.hadoop.hbase.client.BufferedMutatorParams	Parameters for instantiating a BufferedMutator.
CheckAndMutate	Used to perform CheckAndMutate operations.
CheckAndMutate.Builder	A builder class for building a CheckAndMutate object.
org.apache.hadoop.hbase.client.CheckAndMutateResult	Represents a result of a CheckAndMutate operation
org.apache.hadoop.hbase.client.ClientAsyncPrefetchScanner	ClientAsyncPrefetchScanner implements async scanner behaviour.
org.apache.hadoop.hbase.client.ClientCoprocessorRpcController	Client side rpc controller for coprocessor implementation.
org.apache.hadoop.hbase.client.ClientScanner	Implements the scanner interface for the HBase client.
org.apache.hadoop.hbase.client.ClientServiceCallable<T>	A RegionServerCallable set to use the Client protocol.
org.apache.hadoop.hbase.client.ClientSideRegionScanner	A client scanner for a region opened for read-only on the client side.
org.apache.hadoop.hbase.client.ClientSimpleScanner	ClientSimpleScanner implements a sync scanner behaviour.
org.apache.hadoop.hbase.client.ClientUtil
org.apache.hadoop.hbase.client.ClusterConnection	Internal methods on Connection that should not be used by user code.
org.apache.hadoop.hbase.client.ColumnFamilyDescriptor	An ColumnFamilyDescriptor contains information about a column family such as the number of versions, compression settings, etc.
org.apache.hadoop.hbase.client.ColumnFamilyDescriptorBuilder
org.apache.hadoop.hbase.client.ColumnFamilyDescriptorBuilder.ModifyableColumnFamilyDescriptor	An ModifyableFamilyDescriptor contains information about a column family such as the number of versions, compression settings, etc.
org.apache.hadoop.hbase.client.CompactionState	POJO representing the compaction state
org.apache.hadoop.hbase.client.CompactType	Currently, there are only two compact types: NORMAL means do store files compaction; MOB means do mob files compaction.
org.apache.hadoop.hbase.client.Connection	A cluster connection encapsulating lower level individual connections to actual servers and a connection to zookeeper.
org.apache.hadoop.hbase.client.ConnectionConfiguration	Configuration parameters for the connection.
org.apache.hadoop.hbase.client.ConnectionFactory	A non-instantiable class that manages creation of Connections.
org.apache.hadoop.hbase.client.ConnectionImplementation	Main implementation of Connection and ClusterConnection interfaces.
org.apache.hadoop.hbase.client.ConnectionRegistry	Registry for meta information needed for connection setup to a HBase cluster.
org.apache.hadoop.hbase.client.ConnectionUtils	Utility used by client connections.
org.apache.hadoop.hbase.client.Consistency	Consistency defines the expected consistency level for an operation.
org.apache.hadoop.hbase.client.CoprocessorDescriptor	CoprocessorDescriptor contains the details about how to build a coprocessor.
org.apache.hadoop.hbase.client.CoprocessorDescriptorBuilder	Used to build the CoprocessorDescriptor
org.apache.hadoop.hbase.client.Cursor	Scan cursor to tell client where server is scanning Scan.setNeedCursorResult(boolean) Result.isCursor() Result.getCursor()
org.apache.hadoop.hbase.client.DelayingRunner	A wrapper for a runnable for a group of actions for a single regionserver.
org.apache.hadoop.hbase.client.Delete	Used to perform Delete operations on a single row.
org.apache.hadoop.hbase.client.DoNotRetryRegionException	Similar to RegionException, but disables retries.
org.apache.hadoop.hbase.client.Durability	Enum describing the durability guarantees for tables and Mutations Note that the items must be sorted in order of increasing durability
org.apache.hadoop.hbase.client.FlushRegionCallable	A Callable for flushRegion() RPC.
org.apache.hadoop.hbase.client.Get	Used to perform Get operations on a single row.
org.apache.hadoop.hbase.client.HBaseAdmin	HBaseAdmin is no longer a client API.
org.apache.hadoop.hbase.client.HBaseAdmin.NamespaceFuture
org.apache.hadoop.hbase.client.HBaseAdmin.ProcedureFuture<V>	Future that waits on a procedure result.
org.apache.hadoop.hbase.client.HBaseAdmin.ProcedureFuture.WaitForStateCallable
org.apache.hadoop.hbase.client.HBaseAdmin.TableFuture<V>
org.apache.hadoop.hbase.client.HBaseHbck	Use Connection.getHbck() to obtain an instance of Hbck instead of constructing an HBaseHbck directly.
org.apache.hadoop.hbase.client.Hbck	Hbck fixup tool APIs.
org.apache.hadoop.hbase.client.HRegionLocator	An implementation of RegionLocator.
org.apache.hadoop.hbase.client.HTable	An implementation of Table.
org.apache.hadoop.hbase.client.HTableMultiplexer	Deprecated. since 2.2.0, will be removed in 3.0.0, without replacement.
org.apache.hadoop.hbase.client.HTableMultiplexer.HTableMultiplexerStatus	Deprecated. since 2.2.0, will be removed in 3.0.0, without replacement.
org.apache.hadoop.hbase.client.ImmutableHColumnDescriptor	Deprecated.
org.apache.hadoop.hbase.client.ImmutableHRegionInfo	Deprecated.
org.apache.hadoop.hbase.client.ImmutableHTableDescriptor	Deprecated.
org.apache.hadoop.hbase.client.ImmutableScan	Immutable version of Scan
org.apache.hadoop.hbase.client.Increment	Used to perform Increment operations on a single row.
org.apache.hadoop.hbase.client.IsolationLevel	Specify Isolation levels in Scan operations.
org.apache.hadoop.hbase.client.LockTimeoutException
LogEntry	Abstract response class representing online logs response from ring-buffer use-cases e.g slow/large RPC logs, balancer decision logs
LogQueryFilter	Deprecated. as of 2.4.0.
org.apache.hadoop.hbase.client.LogQueryFilter.FilterByOperator
org.apache.hadoop.hbase.client.LogQueryFilter.Type
org.apache.hadoop.hbase.client.MasterRegistry	Deprecated. Since 2.5.0, will be removed in 4.0.0.
org.apache.hadoop.hbase.client.MasterSwitchType	Represents the master switch type
org.apache.hadoop.hbase.client.MetaCache	A cache implementation for region locations from meta.
org.apache.hadoop.hbase.client.MetricsConnection	This class is for maintaining the various connection statistics and publishing them through the metrics interfaces.
org.apache.hadoop.hbase.client.MetricsConnection.CallStats	A container class for collecting details about the RPC call as it percolates.
org.apache.hadoop.hbase.client.MetricsConnection.CallTracker
org.apache.hadoop.hbase.client.MetricsConnection.RegionStats
org.apache.hadoop.hbase.client.MetricsConnection.RunnerStats
org.apache.hadoop.hbase.client.MobCompactPartitionPolicy	Enum describing the mob compact partition policy types.
org.apache.hadoop.hbase.client.MultiAction	Container for Actions (i.e.
org.apache.hadoop.hbase.client.MultiResponse	A container for Result objects, grouped by regionName.
org.apache.hadoop.hbase.client.Mutation
org.apache.hadoop.hbase.client.NoncedRegionServerCallable<T>	Implementations make an rpc call against a RegionService via a protobuf Service.
org.apache.hadoop.hbase.client.NonceGenerator	NonceGenerator interface.
org.apache.hadoop.hbase.client.NormalizeTableFilterParams	A collection of criteria used for table selection.
org.apache.hadoop.hbase.client.NormalizeTableFilterParams.Builder	Used to instantiate an instance of NormalizeTableFilterParams.
org.apache.hadoop.hbase.client.NoServerForRegionException	Thrown when no region server can be found for a region
OnlineLogRecord	Slow/Large Log payload for hbase-client, to be used by Admin API get_slow_responses and get_large_responses
org.apache.hadoop.hbase.client.OnlineLogRecord.OnlineLogRecordBuilder
org.apache.hadoop.hbase.client.Operation	Superclass for any type that maps to a potentially application-level query.
org.apache.hadoop.hbase.client.OperationTimeoutExceededException	Thrown when a batch operation exceeds the operation timeout
org.apache.hadoop.hbase.client.OperationWithAttributes
org.apache.hadoop.hbase.client.PackagePrivateFieldAccessor	A helper class used to access the package private field in o.a.h.h.client package.
org.apache.hadoop.hbase.client.PerClientRandomNonceGenerator	NonceGenerator implementation that uses client ID hash + random int as nonce group, and random numbers as nonces.
org.apache.hadoop.hbase.client.Put	Used to perform Put operations for a single row.
org.apache.hadoop.hbase.client.Query	Base class for HBase read operations; e.g.
org.apache.hadoop.hbase.client.RegionAdminServiceCallable<T>	Similar to RegionServerCallable but for the AdminService interface.
org.apache.hadoop.hbase.client.RegionCoprocessorServiceExec	Represents a coprocessor service method execution against a single region.
org.apache.hadoop.hbase.client.RegionInfo	Information about a region.
org.apache.hadoop.hbase.client.RegionInfoBuilder
org.apache.hadoop.hbase.client.RegionInfoDisplay	Utility used composing RegionInfo for 'display'; e.g.
org.apache.hadoop.hbase.client.RegionLoadStats	POJO representing region server load
org.apache.hadoop.hbase.client.RegionLocator	Used to view region location information for a single HBase table.
org.apache.hadoop.hbase.client.RegionOfflineException	Thrown when a table can not be located
org.apache.hadoop.hbase.client.RegionReplicaUtil	Utility methods which contain the logic for regions and replicas.
org.apache.hadoop.hbase.client.RegionServerCallable<T,S>	Implementations make a RPC call against a RegionService via a protobuf Service.
org.apache.hadoop.hbase.client.RegionServerCoprocessorRpcChannelImpl	The implementation of a region server based coprocessor rpc channel.
org.apache.hadoop.hbase.client.RegionServerRegistry	Connection registry implementation for region server.
org.apache.hadoop.hbase.client.RegionStatesCount
org.apache.hadoop.hbase.client.RegionStatesCount.RegionStatesCountBuilder
org.apache.hadoop.hbase.client.RequestController	An interface for client request scheduling algorithm.
org.apache.hadoop.hbase.client.RequestController.Checker	Picks up the valid data.
org.apache.hadoop.hbase.client.RequestController.ReturnCode
org.apache.hadoop.hbase.client.RequestControllerFactory	A factory class that constructs an RequestController.
org.apache.hadoop.hbase.client.Result	Single row result of a Get or Scan query.
org.apache.hadoop.hbase.client.ResultBoundedCompletionService<V>	A completion service for the RpcRetryingCallerFactory.
org.apache.hadoop.hbase.client.ResultScanner	Interface for client-side scanning.
org.apache.hadoop.hbase.client.ResultStatsUtil	Statistics update about a server/region
org.apache.hadoop.hbase.client.RetriesExhaustedException	Exception thrown by HTable methods when an attempt to do something (like commit changes) fails after a bunch of retries.
org.apache.hadoop.hbase.client.RetriesExhaustedException.ThrowableWithExtraContext	Data structure that allows adding more info around Throwable incident.
org.apache.hadoop.hbase.client.RetriesExhaustedWithDetailsException	This subclass of RetriesExhaustedException is thrown when we have more information about which rows were causing which exceptions on what servers.
org.apache.hadoop.hbase.client.RetryingCallable<T>	A Callable<T> that will be retried.
org.apache.hadoop.hbase.client.ReversedClientScanner	A reversed client scanner which support backward scanning
org.apache.hadoop.hbase.client.ReversedScannerCallable	A reversed ScannerCallable which supports backward scanning.
org.apache.hadoop.hbase.client.Row	Has a row.
org.apache.hadoop.hbase.client.RowAccess<T>	Provide a way to access the inner buffer.
org.apache.hadoop.hbase.client.RowMutations	Performs multiple mutations atomically on a single row.
org.apache.hadoop.hbase.client.RowTooBigException	Gets or Scans throw this exception if running without in-row scan flag set and row size appears to exceed max configured size (configurable via hbase.table.max.rowsize).
org.apache.hadoop.hbase.client.RpcConnectionRegistry	Rpc based connection registry.
org.apache.hadoop.hbase.client.RpcRetryingCaller<T>
org.apache.hadoop.hbase.client.RpcRetryingCallerFactory	Factory to create an RpcRetryingCaller
org.apache.hadoop.hbase.client.RpcRetryingCallerImpl<T>	Runs an rpc'ing RetryingCallable.
org.apache.hadoop.hbase.client.RpcRetryingCallerWithReadReplicas	Caller that goes to replica if the primary region does no answer within a configurable timeout.
org.apache.hadoop.hbase.client.Scan	Used to perform Scan operations.
org.apache.hadoop.hbase.client.Scan.ReadType
org.apache.hadoop.hbase.client.ScannerCallable	Scanner operations such as create, next, etc.
org.apache.hadoop.hbase.client.ScanResultConsumer	Receives Result for an asynchronous scan.
org.apache.hadoop.hbase.client.ScanResultConsumerBase	The base interface for scan result consumer.
org.apache.hadoop.hbase.client.SecureBulkLoadClient	Client proxy for SecureBulkLoadProtocol
org.apache.hadoop.hbase.client.ServerConnectionUtils
org.apache.hadoop.hbase.client.ServerConnectionUtils.ShortCircuitingClusterConnection	A ClusterConnection that will short-circuit RPC making direct invocations against the localhost if the invocation target is 'this' server; save on network and protobuf invocations.
org.apache.hadoop.hbase.client.ServerStatisticTracker	Tracks the statistics for multiple regions
org.apache.hadoop.hbase.client.ServerType	Select server type i.e destination for RPC request associated with ring buffer.
org.apache.hadoop.hbase.client.ServiceCaller<S,R>	Delegate to a protobuf rpc call.
org.apache.hadoop.hbase.client.ShortCircuitMasterConnection	A short-circuit connection that can bypass the RPC layer (serialization, deserialization, networking, etc..) when talking to a local master
org.apache.hadoop.hbase.client.SingleResponse	Class for single action response
org.apache.hadoop.hbase.client.SingleResponse.Entry
org.apache.hadoop.hbase.client.SlowLogParams	SlowLog params object that contains detailed info as params and region name : to be used for filter purpose
org.apache.hadoop.hbase.client.SnapshotDescription	The POJO equivalent of HBaseProtos.SnapshotDescription
org.apache.hadoop.hbase.client.SnapshotType	POJO representing the snapshot type
org.apache.hadoop.hbase.client.StatisticTrackable	Parent interface for an object to get updates about per-region statistics.
org.apache.hadoop.hbase.client.Table	Used to communicate with a single HBase table.
org.apache.hadoop.hbase.client.Table.CheckAndMutateBuilder	Deprecated. Since 2.4.0, will be removed in 4.0.0.
org.apache.hadoop.hbase.client.Table.CheckAndMutateWithFilterBuilder	Deprecated. Since 2.4.0, will be removed in 4.0.0.
org.apache.hadoop.hbase.client.TableBuilder	For creating Table instance.
org.apache.hadoop.hbase.client.TableDescriptor	TableDescriptor contains the details about an HBase table such as the descriptors of all the column families, is the table a catalog table, hbase:meta , if the table is read only, the maximum size of the memstore, when the region split should occur, coprocessors associated with it etc...
org.apache.hadoop.hbase.client.TableDescriptorBuilder	Convenience class for composing an instance of TableDescriptor.
org.apache.hadoop.hbase.client.TableDescriptorBuilder.ModifyableTableDescriptor	TODO: make this private after removing the HTableDescriptor
org.apache.hadoop.hbase.client.TableDescriptorUtils
org.apache.hadoop.hbase.client.TableDescriptorUtils.TableDescriptorDelta
org.apache.hadoop.hbase.client.TableSnapshotScanner	A Scanner which performs a scan over snapshot files.
org.apache.hadoop.hbase.client.TableState	Represents table state.
org.apache.hadoop.hbase.client.TableState.State
org.apache.hadoop.hbase.client.VersionInfoUtil	Class to help with parsing the version info.
org.apache.hadoop.hbase.client.WrongRowIOException