| Package | Description | 
|---|---|
| org.apache.hadoop.conf | Configuration of system parameters. | 
| org.apache.hadoop.fs | Implementations of  AbstractFileSystemfor hdfs
    over rpc and hdfs over web. | 
| org.apache.hadoop.fs.adl | Supporting classes for metrics instrumentation. | 
| org.apache.hadoop.fs.azure | 
A distributed implementation of  FileSystemfor reading and writing files on
Azure Block Storage. | 
| org.apache.hadoop.fs.ftp | |
| org.apache.hadoop.fs.s3native | 
A distributed implementation of  FileSystemfor reading and writing files on
Amazon S3. | 
| org.apache.hadoop.fs.viewfs | ViewFileSystem and ViewFileSystemOverloadScheme classes. | 
| org.apache.hadoop.hdfs.server.aliasmap | |
| org.apache.hadoop.hdfs.server.common.blockaliasmap.impl | |
| org.apache.hadoop.hdfs.server.namenode | |
| org.apache.hadoop.hdfs.web.oauth2 | OAuth2-based WebHDFS authentication. | 
| org.apache.hadoop.io | Generic i/o code for use when reading and writing data to the network,
to databases, and to files. | 
| org.apache.hadoop.io.compress | |
| org.apache.hadoop.io.serializer | 
This package provides a mechanism for using different serialization frameworks
in Hadoop. | 
| org.apache.hadoop.io.serializer.avro | 
This package provides Avro serialization in Hadoop. | 
| org.apache.hadoop.mapred | |
| org.apache.hadoop.mapred.join | |
| org.apache.hadoop.mapred.pipes | |
| org.apache.hadoop.mapreduce.lib.db | |
| org.apache.hadoop.mapreduce.lib.partition | |
| org.apache.hadoop.mapreduce.tools | |
| org.apache.hadoop.net | Network-related classes. | 
| org.apache.hadoop.record | 
    (DEPRECATED) Hadoop record I/O contains classes and a record description language
    translator for simplifying serialization and deserialization of records in a
    language-neutral manner. | 
| org.apache.hadoop.security.authorize | |
| org.apache.hadoop.tools | Command-line tools for MapReduce. | 
| org.apache.hadoop.util | Common utilities. | 
| org.apache.hadoop.yarn.client.cli | |
| org.apache.hadoop.yarn.util | 
| Modifier and Type | Class and Description | 
|---|---|
| class  | ConfiguredBase class for things that may be configured with a  Configuration. | 
| Modifier and Type | Class and Description | 
|---|---|
| class  | ChecksumFileSystemAbstract Checksumed FileSystem. | 
| class  | FileSystemAn abstract base class for a fairly generic filesystem. | 
| class  | FilterFileSystemA  FilterFileSystemcontains
 some other file system, which it uses as
 its  basic file system, possibly transforming
 the data along the way or providing  additional
 functionality. | 
| class  | LocalFileSystemImplement the FileSystem API for the checksumed local filesystem. | 
| class  | RawLocalFileSystemImplement the FileSystem API for the raw local filesystem. | 
| class  | TrashProvides a trash facility which supports pluggable Trash policies. | 
| class  | TrashPolicyThis interface is used for implementing different Trash policies. | 
| Modifier and Type | Class and Description | 
|---|---|
| class  | AdlFileSystemA FileSystem to access Azure Data Lake Store. | 
| Modifier and Type | Class and Description | 
|---|---|
| class  | NativeAzureFileSystemA  FileSystemfor reading and writing files stored on Windows Azure. | 
| class  | WasbFsckAn fsck tool implementation for WASB that does various admin/cleanup/recovery
 tasks on the WASB file system. | 
| Modifier and Type | Class and Description | 
|---|---|
| class  | FTPFileSystem
 A  FileSystembacked by an FTP client provided by Apache Commons Net. | 
| Modifier and Type | Class and Description | 
|---|---|
| class  | NativeS3FileSystemDeprecated. 
 Replaced by the S3A client. | 
| Modifier and Type | Class and Description | 
|---|---|
| class  | ViewFileSystemViewFileSystem (extends the FileSystem interface) implements a client-side
 mount table. | 
| Modifier and Type | Class and Description | 
|---|---|
| class  | InMemoryAliasMapInMemoryAliasMap is an implementation of the InMemoryAliasMapProtocol for
 use with LevelDB. | 
| Modifier and Type | Class and Description | 
|---|---|
| class  | LevelDBFileRegionAliasMapA LevelDB based implementation of  BlockAliasMap. | 
| class  | TextFileRegionAliasMapThis class is used for block maps stored as text files,
 with a specified delimiter. | 
| Modifier and Type | Class and Description | 
|---|---|
| class  | FileSystemImageCreate FSImage from an external namespace. | 
| class  | FixedBlockMultiReplicaResolverResolver mapping all files to a configurable, uniform blocksize
 and replication. | 
| class  | FixedBlockResolverResolver mapping all files to a configurable, uniform blocksize. | 
| class  | SingleUGIResolverMap all owners/groups in external system to a single user in FSImage. | 
| Modifier and Type | Class and Description | 
|---|---|
| class  | AccessTokenProviderProvide an OAuth2 access token to be used to authenticate http calls in
 WebHDFS. | 
| class  | ConfCredentialBasedAccessTokenProviderObtain an access token via a a credential (provided through the
 Configuration) using the
 
   Client Credentials Grant workflow. | 
| class  | ConfRefreshTokenBasedAccessTokenProviderSupply a access token obtained via a refresh token (provided through the
 Configuration using the second half of the
 
   Authorization Code Grant workflow. | 
| class  | CredentialBasedAccessTokenProviderObtain an access token via the credential-based OAuth2 workflow. | 
| Modifier and Type | Class and Description | 
|---|---|
| class  | AbstractMapWritableAbstract base class for MapWritable and SortedMapWritable
 
 Unlike org.apache.nutch.crawl.MapWritable, this class allows creation of
 MapWritable<Writable, MapWritable> so the CLASS_TO_ID and ID_TO_CLASS
 maps travel with the class instead of being static. | 
| class  | EnumSetWritable<E extends Enum<E>>A Writable wrapper for EnumSet. | 
| class  | GenericWritableA wrapper for Writable instances. | 
| class  | MapWritableA Writable Map. | 
| class  | ObjectWritableA polymorphic Writable that writes an instance with it's class name. | 
| class  | SortedMapWritable<K extends WritableComparable<? super K>>A Writable SortedMap. | 
| class  | WritableComparatorA Comparator for  WritableComparables. | 
| Modifier and Type | Class and Description | 
|---|---|
| class  | BZip2CodecThis class provides output and input streams for bzip2 compression
 and decompression. | 
| class  | DefaultCodec | 
| class  | GzipCodecThis class creates gzip compressors/decompressors. | 
| Modifier and Type | Class and Description | 
|---|---|
| class  | WritableSerializationA  SerializationforWritables that delegates toWritable.write(java.io.DataOutput)andWritable.readFields(java.io.DataInput). | 
| Modifier and Type | Class and Description | 
|---|---|
| class  | AvroReflectSerializationSerialization for Avro Reflect classes. | 
| class  | AvroSerialization<T>Base class for providing serialization to Avro types. | 
| class  | AvroSpecificSerializationSerialization for Avro Specific classes. | 
| Modifier and Type | Class and Description | 
|---|---|
| class  | JobClientJobClientis the primary interface for the user-job to interact
 with the cluster. | 
| Modifier and Type | Class and Description | 
|---|---|
| class  | CompositeRecordReader<K extends WritableComparable,V extends Writable,X extends Writable>A RecordReader that can effect joins of RecordReaders sharing a common key
 type and partitioning. | 
| class  | InnerJoinRecordReader<K extends WritableComparable>Full inner join. | 
| class  | JoinRecordReader<K extends WritableComparable>Base class for Composite joins returning Tuples of arbitrary Writables. | 
| class  | MultiFilterRecordReader<K extends WritableComparable,V extends Writable>Base class for Composite join returning values derived from multiple
 sources, but generally not tuples. | 
| class  | OuterJoinRecordReader<K extends WritableComparable>Full outer join. | 
| class  | OverrideRecordReader<K extends WritableComparable,V extends Writable>Prefer the "rightmost" data source for this key. | 
| class  | WrappedRecordReader<K extends WritableComparable,U extends Writable>Proxy class for a RecordReader participating in the join framework. | 
| Modifier and Type | Class and Description | 
|---|---|
| class  | SubmitterThe main entry point and job submitter. | 
| Modifier and Type | Class and Description | 
|---|---|
| class  | DataDrivenDBInputFormat<T extends DBWritable>A InputFormat that reads input data from an SQL table. | 
| class  | DBInputFormat<T extends DBWritable>A InputFormat that reads input data from an SQL table. | 
| class  | OracleDataDrivenDBInputFormat<T extends DBWritable>A InputFormat that reads input data from an SQL table in an Oracle db. | 
| Modifier and Type | Class and Description | 
|---|---|
| class  | BinaryPartitioner<V>Partition  BinaryComparablekeys using a configurable part of 
 the bytes array returned byBinaryComparable.getBytes(). | 
| class  | InputSampler<K,V>Utility for collecting samples and writing a partition file for
  TotalOrderPartitioner. | 
| class  | KeyFieldBasedComparator<K,V>This comparator implementation provides a subset of the features provided
 by the Unix/GNU Sort. | 
| class  | KeyFieldBasedPartitioner<K2,V2>Defines a way to partition keys based on certain key fields (also see
   KeyFieldBasedComparator. | 
| class  | TotalOrderPartitioner<K,V>Partitioner effecting a total order by reading split points from
 an externally generated source. | 
| Modifier and Type | Class and Description | 
|---|---|
| class  | CLIInterprets the map reduce cli options | 
| Modifier and Type | Class and Description | 
|---|---|
| class  | AbstractDNSToSwitchMappingThis is a base class for DNS to Switch mappings. | 
| class  | CachedDNSToSwitchMappingA cached implementation of DNSToSwitchMapping that takes an
 raw DNSToSwitchMapping and stores the resolved network location in 
 a cache. | 
| class  | ScriptBasedMappingThis class implements the  DNSToSwitchMappinginterface using a 
 script configured via theCommonConfigurationKeysPublic.NET_TOPOLOGY_SCRIPT_FILE_NAME_KEYoption. | 
| class  | SocksSocketFactorySpecialized SocketFactory to create sockets with a SOCKS proxy | 
| class  | TableMapping
 Simple  DNSToSwitchMappingimplementation that reads a 2 column text
 file. | 
| Modifier and Type | Class and Description | 
|---|---|
| class  | RecordComparatorDeprecated. 
 Replaced by Avro. | 
| Modifier and Type | Interface and Description | 
|---|---|
| interface  | ImpersonationProvider | 
| Modifier and Type | Class and Description | 
|---|---|
| class  | DefaultImpersonationProvider | 
| Modifier and Type | Class and Description | 
|---|---|
| class  | DistCpDistCp is the main driver-class for DistCpV2. | 
| Modifier and Type | Interface and Description | 
|---|---|
| interface  | ToolA tool interface that supports handling of generic command-line options. | 
| Modifier and Type | Class and Description | 
|---|---|
| class  | LogsCLI | 
| class  | SchedConfCLICLI for modifying scheduler configuration. | 
| Modifier and Type | Class and Description | 
|---|---|
| class  | ResourceCalculatorProcessTreeInterface class to obtain process resource usage
 NOTE: This class should not be used by external users, but only by external
 developers to extend and include their own process-tree implementation, 
 especially for platforms other than Linux and Windows. | 
Copyright © 2022 Apache Software Foundation. All rights reserved.