## Package org.apache.hadoop.util

Common utilities.

See:
Description

Interface Summary
IndexedSortable: Interface for collections capable of being sorted by `IndexedSorter` algorithms.
IndexedSorter: Interface for sort algorithms accepting `IndexedSortable` items.
Progressable: A facility for reporting progress.
ServicePlugin: Service plug-in interface.
Tool: A tool interface that supports handling of generic command-line options.

Class Summary
ChecksumUtil
ClassUtil
CyclicIteration<K,V>: Provide an cyclic `Iterator` for a `NavigableMap`.
Daemon: A thread that has called `Thread.setDaemon(boolean)` with true.
DataChecksum: This class provides inteface and utilities for processing checksums for DFS data transfers.
DiskChecker: Class that provides utility functions for checking disk problem
GenericOptionsParser: `GenericOptionsParser` is a utility to parse command line arguments generic to the Hadoop framework.
GenericsUtil: Contains utility methods for dealing with Java Generics.
HeapSort: An implementation of the core algorithm of HeapSort.
HostsFileReader
LineReader: A class that provides a line reader from an input stream.
LinuxMemoryCalculatorPlugin: Deprecated. Use `LinuxResourceCalculatorPlugin` instead
LinuxResourceCalculatorPlugin: Plugin to calculate resource information on Linux systems.
MemoryCalculatorPlugin: Deprecated. Use `ResourceCalculatorPlugin` instead
MergeSort: An implementation of the core algorithm of MergeSort.
NativeCodeLoader: A helper to load the native hadoop code i.e.
PlatformName: A helper class for getting build-info of the java-vm.
PrintJarMainClass: A micro-application that prints the main class name out of a jar file.
PriorityQueue<T>: A PriorityQueue maintains a partial ordering of its elements such that the least element can always be found in constant time.
ProcessTree: Process tree related operations
ProcfsBasedProcessTree: A Proc file-system based ProcessTree.
ProgramDriver: A driver that is used to run programs added to it
Progress: Utility to assist with generation of progress reports.
PureJavaCrc32: A pure-java implementation of the CRC32 checksum that uses the same polynomial as the built-in native CRC32.
QueueProcessingStatistics: Hadoop has several work queues, such as `FSNamesystem.neededReplications` With a properly throttled queue, a worker thread cycles repeatedly, doing a chunk of work each cycle then resting a bit, until the queue is empty.
QuickSort: An implementation of the core algorithm of QuickSort.
ReflectionUtils: General reflection utils
ResourceCalculatorPlugin: Plugin to calculate resource information on the system.
ResourceCalculatorPlugin.ProcResourceValues
RunJar: Run a Hadoop job jar.
ServletUtil
Shell: A base class for running a Unix command.
Shell.ShellCommandExecutor: A simple shell command executor.
StringUtils: General string utils
ToolRunner: A utility to help run `Tool`s.
UTF8ByteArrayUtils
VersionInfo: This class finds the package info for Hadoop and the HadoopVersionAnnotation information.
XMLUtils: General xml utilities.

Enum Summary
ProcessTree.Signal: The constants for the signals.
QueueProcessingStatistics.State: This enum provides the "states" of a state machine for `QueueProcessingStatistics`.
StringUtils.TraditionalBinaryPrefix: The traditional binary prefixes, kilo, mega, ..., exa, which can be represented by a 64-bit integer.

Exception Summary
DiskChecker.DiskErrorException
DiskChecker.DiskOutOfSpaceException
Shell.ExitCodeException: This is an IOException with exit code added.

## Package org.apache.hadoop.util Description

Common utilities.

Copyright © 2009 The Apache Software Foundation