Packages 
Package Description
com.puppycrawl.tools.checkstyle
Contains the implementation of the Checkstyle framework.
com.puppycrawl.tools.checkstyle.ant
Contains code related to Checkstyle Ant Task.
com.puppycrawl.tools.checkstyle.api
Contains the core API to be used to implement checks.
com.puppycrawl.tools.checkstyle.checks
Contains the checks that are bundled with the main distribution.
com.puppycrawl.tools.checkstyle.checks.annotation
Contains the Annotation checks that are bundled with the main distribution.
com.puppycrawl.tools.checkstyle.checks.blocks
Contains the Block checks that are bundled with the main distribution.
com.puppycrawl.tools.checkstyle.checks.coding
Contains the Coding checks that are bundled with the main distribution.
com.puppycrawl.tools.checkstyle.checks.design
Contains the Class Design checks that are bundled with the main distribution.
com.puppycrawl.tools.checkstyle.checks.header
File Header checks.
com.puppycrawl.tools.checkstyle.checks.imports
Contains the Imports checks that are bundled with the main distribution.
com.puppycrawl.tools.checkstyle.checks.indentation
Contains all classes required for the indentation check.
com.puppycrawl.tools.checkstyle.checks.javadoc
Contains the Javadoc checks that are bundled with the main distribution.
com.puppycrawl.tools.checkstyle.checks.javadoc.utils
Contains utils classes for the Javadoc checks that are bundled with the main distribution.
com.puppycrawl.tools.checkstyle.checks.metrics
Contains the Metrics checks that are bundled with the main distribution.
com.puppycrawl.tools.checkstyle.checks.modifier
Contains the modifier checks that are bundled with the main distribution.
com.puppycrawl.tools.checkstyle.checks.naming
Contains the Naming conventions checks that are bundled with the main distribution.
com.puppycrawl.tools.checkstyle.checks.regexp
Contains the regular expression checks that are bundled with the main distribution.
com.puppycrawl.tools.checkstyle.checks.sizes
Contains the Size Violations checks that are bundled with the main distribution.
com.puppycrawl.tools.checkstyle.checks.whitespace
Contains the Whitespace checks that are bundled with the main distribution.
com.puppycrawl.tools.checkstyle.filefilters
Contains the before execution file filters that are bundled with the main distribution.
com.puppycrawl.tools.checkstyle.filters
Contains the filters that are bundled with the main distribution.
com.puppycrawl.tools.checkstyle.grammar
Contains the grammar used by the Checkstyle framework.
com.puppycrawl.tools.checkstyle.grammar.javadoc  
com.puppycrawl.tools.checkstyle.gui
User interface classes for CheckStyle.
com.puppycrawl.tools.checkstyle.meta
Contains module metadata generation classes for checkstyle.
com.puppycrawl.tools.checkstyle.utils
Contains utils classes for checkstyle.
com.puppycrawl.tools.checkstyle.xpath
Contains the nodes implementations for XPATH queries and query generator.