## Uses of Package
org.apache.hadoop.mapred

Packages that use org.apache.hadoop.mapred
org.apache.hadoop.contrib.index.example
org.apache.hadoop.contrib.index.mapred
org.apache.hadoop.contrib.utils.join
org.apache.hadoop.examples: Hadoop example code.
org.apache.hadoop.examples.dancing: This package is a distributed implementation of Knuth's dancing links algorithm that can run under Hadoop.
org.apache.hadoop.examples.terasort: This package consists of 3 map/reduce applications for Hadoop to compete in the annual terabyte sort competition.
org.apache.hadoop.filecache
org.apache.hadoop.mapred: A software framework for easily writing applications which process vast amounts of data (multi-terabyte data-sets) parallelly on large clusters (thousands of nodes) built of commodity hardware in a reliable, fault-tolerant manner.
org.apache.hadoop.mapred.jobcontrol: Utilities for managing dependent jobs.
org.apache.hadoop.mapred.join: Given a set of sorted datasets keyed with the same class and yielding equal partitions, it is possible to effect a join of those datasets prior to the map.
org.apache.hadoop.mapred.lib: Library of generally useful mappers, reducers, and partitioners.
org.apache.hadoop.mapred.lib.aggregate: Classes for performing various counting and aggregations.
org.apache.hadoop.mapred.lib.db: org.apache.hadoop.mapred.lib.db Package
org.apache.hadoop.mapred.pipes: Hadoop Pipes allows C++ code to use Hadoop DFS and map/reduce.
org.apache.hadoop.mapreduce
org.apache.hadoop.mapreduce.server.jobtracker
org.apache.hadoop.mapreduce.server.tasktracker
org.apache.hadoop.mapreduce.server.tasktracker.userlogs
org.apache.hadoop.mapreduce.split
org.apache.hadoop.streaming: `Hadoop Streaming` is a utility which allows users to create and run Map-Reduce jobs with any executables (e.g.

Classes in org.apache.hadoop.mapred used by org.apache.hadoop.contrib.index.example
FileInputFormat A base class for file-based `InputFormat`.
FileSplit A section of an input file.
InputFormat `InputFormat` describes the input-specification for a Map-Reduce job.
InputSplit `InputSplit` represents the data to be processed by an individual `Mapper`.
JobConf A map/reduce job configuration.
JobConfigurable That what may be configured.
Mapper Maps input key/value pairs to a set of intermediate key/value pairs.
OutputCollector Collects the `<key, value>` pairs output by `Mapper`s and `Reducer`s.
RecordReader `RecordReader` reads <key, value> pairs from an `InputSplit`.
Reporter A facility for Map-Reduce applications to report progress and update counters, status information etc.

Classes in org.apache.hadoop.mapred used by org.apache.hadoop.contrib.index.mapred
FileOutputFormat A base class for `OutputFormat`.
InputFormat `InputFormat` describes the input-specification for a Map-Reduce job.
JobConf A map/reduce job configuration.
JobConfigurable That what may be configured.
Mapper Maps input key/value pairs to a set of intermediate key/value pairs.
MapReduceBase Base class for `Mapper` and `Reducer` implementations.
OutputCollector Collects the `<key, value>` pairs output by `Mapper`s and `Reducer`s.
OutputFormat `OutputFormat` describes the output-specification for a Map-Reduce job.
Partitioner Partitions the key space.
RecordWriter `RecordWriter` writes the output <key, value> pairs to an output file.
Reducer Reduces a set of intermediate values which share a key to a smaller set of values.
Reporter A facility for Map-Reduce applications to report progress and update counters, status information etc.

Classes in org.apache.hadoop.mapred used by org.apache.hadoop.contrib.utils.join
JobConf A map/reduce job configuration.
JobConfigurable That what may be configured.
Mapper Maps input key/value pairs to a set of intermediate key/value pairs.
OutputCollector Collects the `<key, value>` pairs output by `Mapper`s and `Reducer`s.
Reducer Reduces a set of intermediate values which share a key to a smaller set of values.
Reporter A facility for Map-Reduce applications to report progress and update counters, status information etc.

Classes in org.apache.hadoop.mapred used by org.apache.hadoop.examples
FileInputFormat A base class for file-based `InputFormat`.
InputFormat `InputFormat` describes the input-specification for a Map-Reduce job.
InputSplit `InputSplit` represents the data to be processed by an individual `Mapper`.
JobConf A map/reduce job configuration.
JobConfigurable That what may be configured.
Mapper Maps input key/value pairs to a set of intermediate key/value pairs.
MapReduceBase Base class for `Mapper` and `Reducer` implementations.
MultiFileInputFormat Deprecated. Use `CombineFileInputFormat` instead
MultiFileSplit Deprecated. Use `CombineFileSplit` instead
OutputCollector Collects the `<key, value>` pairs output by `Mapper`s and `Reducer`s.
Partitioner Partitions the key space.
RecordReader `RecordReader` reads <key, value> pairs from an `InputSplit`.
Reducer Reduces a set of intermediate values which share a key to a smaller set of values.
Reporter A facility for Map-Reduce applications to report progress and update counters, status information etc.
RunningJob `RunningJob` is the user-interface to query for details on a running Map-Reduce job.

Classes in org.apache.hadoop.mapred used by org.apache.hadoop.examples.dancing
JobConf A map/reduce job configuration.
JobConfigurable That what may be configured.
Mapper Maps input key/value pairs to a set of intermediate key/value pairs.
MapReduceBase Base class for `Mapper` and `Reducer` implementations.
OutputCollector Collects the `<key, value>` pairs output by `Mapper`s and `Reducer`s.
Reporter A facility for Map-Reduce applications to report progress and update counters, status information etc.

Classes in org.apache.hadoop.mapred used by org.apache.hadoop.examples.terasort
FileInputFormat A base class for file-based `InputFormat`.
FileOutputFormat A base class for `OutputFormat`.
InputFormat `InputFormat` describes the input-specification for a Map-Reduce job.
InputSplit `InputSplit` represents the data to be processed by an individual `Mapper`.
JobConf A map/reduce job configuration.
JobConfigurable That what may be configured.
Mapper Maps input key/value pairs to a set of intermediate key/value pairs.
MapReduceBase Base class for `Mapper` and `Reducer` implementations.
OutputCollector Collects the `<key, value>` pairs output by `Mapper`s and `Reducer`s.
OutputFormat `OutputFormat` describes the output-specification for a Map-Reduce job.
RecordReader `RecordReader` reads <key, value> pairs from an `InputSplit`.
RecordWriter `RecordWriter` writes the output <key, value> pairs to an output file.
Reporter A facility for Map-Reduce applications to report progress and update counters, status information etc.
TextOutputFormat An `OutputFormat` that writes plain text files.

Classes in org.apache.hadoop.mapred used by org.apache.hadoop.filecache
InvalidJobConfException This exception is thrown when jobconf misses some mendatory attributes or value of some attributes is invalid.
TaskController Controls initialization, finalization and clean up of tasks, and also the launching and killing of task JVMs.

Classes in org.apache.hadoop.mapred used by org.apache.hadoop.mapred
AdminOperationsProtocol Protocol for admin operations.
ClusterStatus Status information on the current state of the Map-Reduce cluster.
Counters A set of named counters.
Counters.Counter A counter record, comprising its name and value.
Counters.Group `Group` of counters, comprising of counters from a particular counter `Enum` class.
FileAlreadyExistsException Used when target file already exists for any operation and is not configured to be overwritten.
FileInputFormat A base class for file-based `InputFormat`.
FileInputFormat.Counter
FileOutputFormat A base class for `OutputFormat`.
FileOutputFormat.Counter
FileSplit A section of an input file.
InputFormat `InputFormat` describes the input-specification for a Map-Reduce job.
InputSplit `InputSplit` represents the data to be processed by an individual `Mapper`.
InvalidJobConfException This exception is thrown when jobconf misses some mendatory attributes or value of some attributes is invalid.
JobClient.TaskStatusFilter
JobConf A map/reduce job configuration.
JobConfigurable That what may be configured.
JobContext
JobHistory.JobInfo Helper class for logging or reading back events related to job start, finish or failure.
JobHistory.Keys Job history files contain key="value" pairs, where keys belong to this enum.
JobHistory.Listener Callback interface for reading back log events from JobHistory.
JobHistory.RecordTypes Record types are identifiers for each line of log in history files.
JobHistory.Task Helper class for logging or reading back events related to Task's start, finish or failure.
JobHistory.TaskAttempt Base class for Map and Reduce TaskAttempts.
JobHistory.Values This enum contains some of the values commonly used by history log events.
JobID JobID represents the immutable and unique identifier for the job.
JobInProgress JobInProgress maintains all the info for keeping a Job on the straight and narrow.
JobInProgress.Counter
JobPriority Used to describe the priority of the running job.
JobProfile A JobProfile is a MapReduce primitive.
JobQueueInfo Class that contains the information regarding the Job Queues which are maintained by the Hadoop Map/Reduce framework.
JobStatus Describes the current status of a job.
JobTracker JobTracker is the central location for submitting and tracking MR jobs in a network environment.
JobTracker.State
JobTrackerMXBean The MXBean interface for JobTrackerInfo
JvmTask
Mapper Maps input key/value pairs to a set of intermediate key/value pairs.
MapRunnable Expert: Generic interface for `Mapper`s.
MapTaskCompletionEventsUpdate A class that represents the communication between the tasktracker and child tasks w.r.t the map task completion events.
Operation Generic operation that maps to the dependent set of ACLs that drive the authorization of the operation.
OutputCollector Collects the `<key, value>` pairs output by `Mapper`s and `Reducer`s.
OutputCommitter `OutputCommitter` describes the commit of task output for a Map-Reduce job.
OutputFormat `OutputFormat` describes the output-specification for a Map-Reduce job.
Partitioner Partitions the key space.
QueueAclsInfo Class to encapsulate Queue ACLs for a particular user.
RawKeyValueIterator `RawKeyValueIterator` is an iterator used to iterate over the raw keys and values during sort/merge of intermediate data.
RecordReader `RecordReader` reads <key, value> pairs from an `InputSplit`.
RecordWriter `RecordWriter` writes the output <key, value> pairs to an output file.
Reducer Reduces a set of intermediate values which share a key to a smaller set of values.
Reporter A facility for Map-Reduce applications to report progress and update counters, status information etc.
RunningJob `RunningJob` is the user-interface to query for details on a running Map-Reduce job.
SequenceFileInputFilter.Filter filter interface
SequenceFileInputFilter.FilterBase base class for Filters
SequenceFileInputFormat An `InputFormat` for `SequenceFile`s.
SequenceFileOutputFormat An `OutputFormat` that writes `SequenceFile`s.
Task Base class for tasks.
Task.CombinerRunner
Task.Counter
Task.TaskReporter
TaskAttemptContext
TaskAttemptID TaskAttemptID represents the immutable and unique identifier for a task attempt.
TaskCompletionEvent This is used to track task completion events on job tracker.
TaskCompletionEvent.Status
TaskController Controls initialization, finalization and clean up of tasks, and also the launching and killing of task JVMs.
TaskID TaskID represents the immutable and unique identifier for a Map or Reduce Task.
TaskLog.LogName The filter for userlogs.
TaskReport A report on the state of a task.
TaskStatus Describes the current status of a task.
TaskStatus.Phase
TaskStatus.State
TaskTracker TaskTracker is a process that starts and tracks MR Tasks in a networked environment.
TaskTrackerMXBean MXBean interface for TaskTracker
TaskTrackerStatus A TaskTrackerStatus is a MapReduce primitive.
TaskUmbilicalProtocol Protocol that task child process uses to contact its parent process.
TIPStatus The states of a `TaskInProgress` as seen by the JobTracker.
Utils.OutputFileUtils.OutputLogFilter This class filters log files from directory given It doesnt accept paths having _logs.

Classes in org.apache.hadoop.mapred used by org.apache.hadoop.mapred.jobcontrol
JobClient `JobClient` is the primary interface for the user-job to interact with the `JobTracker`.
JobConf A map/reduce job configuration.
JobID JobID represents the immutable and unique identifier for the job.

Classes in org.apache.hadoop.mapred used by org.apache.hadoop.mapred.join
InputFormat `InputFormat` describes the input-specification for a Map-Reduce job.
InputSplit `InputSplit` represents the data to be processed by an individual `Mapper`.
JobConf A map/reduce job configuration.
RecordReader `RecordReader` reads <key, value> pairs from an `InputSplit`.
Reporter A facility for Map-Reduce applications to report progress and update counters, status information etc.

Classes in org.apache.hadoop.mapred used by org.apache.hadoop.mapred.lib
FileInputFormat A base class for file-based `InputFormat`.
FileOutputFormat A base class for `OutputFormat`.
InputFormat `InputFormat` describes the input-specification for a Map-Reduce job.
InputSplit `InputSplit` represents the data to be processed by an individual `Mapper`.
JobConf A map/reduce job configuration.
JobConfigurable That what may be configured.
Mapper Maps input key/value pairs to a set of intermediate key/value pairs.
MapReduceBase Base class for `Mapper` and `Reducer` implementations.
MapRunnable Expert: Generic interface for `Mapper`s.
OutputCollector Collects the `<key, value>` pairs output by `Mapper`s and `Reducer`s.
OutputFormat `OutputFormat` describes the output-specification for a Map-Reduce job.
Partitioner Partitions the key space.
RecordReader `RecordReader` reads <key, value> pairs from an `InputSplit`.
RecordWriter `RecordWriter` writes the output <key, value> pairs to an output file.
Reducer Reduces a set of intermediate values which share a key to a smaller set of values.
Reporter A facility for Map-Reduce applications to report progress and update counters, status information etc.

Classes in org.apache.hadoop.mapred used by org.apache.hadoop.mapred.lib.aggregate
JobConf A map/reduce job configuration.
JobConfigurable That what may be configured.
Mapper Maps input key/value pairs to a set of intermediate key/value pairs.
OutputCollector Collects the `<key, value>` pairs output by `Mapper`s and `Reducer`s.
Reducer Reduces a set of intermediate values which share a key to a smaller set of values.
Reporter A facility for Map-Reduce applications to report progress and update counters, status information etc.

Classes in org.apache.hadoop.mapred used by org.apache.hadoop.mapred.lib.db
InputFormat `InputFormat` describes the input-specification for a Map-Reduce job.
InputSplit `InputSplit` represents the data to be processed by an individual `Mapper`.
JobConf A map/reduce job configuration.
JobConfigurable That what may be configured.
OutputFormat `OutputFormat` describes the output-specification for a Map-Reduce job.
RecordReader `RecordReader` reads <key, value> pairs from an `InputSplit`.
RecordWriter `RecordWriter` writes the output <key, value> pairs to an output file.
Reporter A facility for Map-Reduce applications to report progress and update counters, status information etc.

Classes in org.apache.hadoop.mapred used by org.apache.hadoop.mapred.pipes
JobConf A map/reduce job configuration.
RunningJob `RunningJob` is the user-interface to query for details on a running Map-Reduce job.

Classes in org.apache.hadoop.mapred used by org.apache.hadoop.mapreduce
ID A general identifier, which internally stores the id as an integer.
JobClient `JobClient` is the primary interface for the user-job to interact with the `JobTracker`.
RawKeyValueIterator `RawKeyValueIterator` is an iterator used to iterate over the raw keys and values during sort/merge of intermediate data.
TaskCompletionEvent This is used to track task completion events on job tracker.

Classes in org.apache.hadoop.mapred used by org.apache.hadoop.mapreduce.server.jobtracker
JobInProgress JobInProgress maintains all the info for keeping a Job on the straight and narrow.
TaskTrackerStatus A TaskTrackerStatus is a MapReduce primitive.

Classes in org.apache.hadoop.mapred used by org.apache.hadoop.mapreduce.server.tasktracker
Task Base class for tasks.

Classes in org.apache.hadoop.mapred used by org.apache.hadoop.mapreduce.server.tasktracker.userlogs
TaskController Controls initialization, finalization and clean up of tasks, and also the launching and killing of task JVMs.
UserLogCleaner This is used only in UserLogManager, to manage cleanup of user logs.

Classes in org.apache.hadoop.mapred used by org.apache.hadoop.mapreduce.split
InputSplit `InputSplit` represents the data to be processed by an individual `Mapper`.

Classes in org.apache.hadoop.mapred used by org.apache.hadoop.streaming
FileInputFormat A base class for file-based `InputFormat`.
FileSplit A section of an input file.
InputFormat `InputFormat` describes the input-specification for a Map-Reduce job.
InputSplit `InputSplit` represents the data to be processed by an individual `Mapper`.
JobClient `JobClient` is the primary interface for the user-job to interact with the `JobTracker`.
JobConf A map/reduce job configuration.
JobConfigurable That what may be configured.
JobID JobID represents the immutable and unique identifier for the job.
KeyValueTextInputFormat An `InputFormat` for plain text files.
Mapper Maps input key/value pairs to a set of intermediate key/value pairs.
MapRunnable Expert: Generic interface for `Mapper`s.
MapRunner Default `MapRunnable` implementation.
OutputCollector Collects the `<key, value>` pairs output by `Mapper`s and `Reducer`s.
RecordReader `RecordReader` reads <key, value> pairs from an `InputSplit`.
Reducer Reduces a set of intermediate values which share a key to a smaller set of values.
Reporter A facility for Map-Reduce applications to report progress and update counters, status information etc.
RunningJob `RunningJob` is the user-interface to query for details on a running Map-Reduce job.

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