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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<!-- Content Stylesheet for Site -->
<!-- start the processing -->
<!-- ====================================================================== -->
<!-- GENERATED FILE, DO NOT EDIT, EDIT THE XML FILE IN xdocs INSTEAD! -->
<!-- Main Page Section -->
<!-- ====================================================================== -->
<html>
<head>
<meta content="text/html; charset=ISO-8859-1" http-equiv="content-type" />
<meta name="author" content="Checkstyle Development Team">
<meta name="email" content="checkstyle-devel@lists.sourceforge.net">
<title>Checkstyle - Coding</title>
<style type="text/css" media="all">
@import url("./css/cs-layout.css");
@import url("./css/cs-style.css");
</style>
</head>
<body>
<div class="csTopBar">
<div class="csTopBarContents">
<div class="csLeft">
<h1>Coding</h1>
</div>
<div class="csRight">
<a href="http://checkstyle.sourceforge.net/">
<img src="images/logo.png" alt="Checkstyle Logo" height="70"/>
</a>
</div>
</div>
</div>
<div class="csMiddleContainer">
<div class="csLeftBar">
<div class="csLeftBarContents">
<!-- ============================================================ -->
<!-- start makeNavigationBar -->
<ul>
<li>
<strong>About</strong>
</li>
<li> <a href="./index.html">Checkstyle</a>
</li>
<li>
<strong>Documentation</strong>
</li>
<li> <a href="./releasenotes.html">Release Notes</a>
</li>
<li> <a href="./config.html">Configuration</a>
</li>
<li> <a href="./property_types.html"> Property Types</a>
</li>
<li> <a href="./running.html">Running</a>
</li>
<li> <a href="./anttask.html"> Ant Task</a>
</li>
<li> <a href="./cmdline.html"> Command Line</a>
</li>
<li> <a href="./availablechecks.html">Available Checks</a>
</li>
<li> <a href="./checks.html">Standard Checks</a>
</li>
<li> <a href="./config_javadoc.html"> Javadoc Comments</a>
</li>
<li> <a href="./config_naming.html"> Naming Conventions</a>
</li>
<li> <a href="./config_header.html"> Headers</a>
</li>
<li> <a href="./config_imports.html"> Imports</a>
</li>
<li> <a href="./config_sizes.html"> Size Violations</a>
</li>
<li> <a href="./config_whitespace.html"> Whitespace</a>
</li>
<li> <a href="./config_modifier.html"> Modifiers</a>
</li>
<li> <a href="./config_blocks.html"> Block Checks</a>
</li>
<li><b> <a href="./config_coding.html"> Coding</a>
</b></li>
<li><a href="#ArrayTrailingComma"> ArrayTrailingComma</a></li>
<li><a href="#AvoidInlineConditionals"> AvoidInlineConditionals</a></li>
<li><a href="#CovariantEquals"> CovariantEquals</a></li>
<li><a href="#DoubleCheckedLocking"> DoubleCheckedLocking</a></li>
<li><a href="#EmptyStatement"> EmptyStatement</a></li>
<li><a href="#EqualsHashCode"> EqualsHashCode</a></li>
<li><a href="#FinalLocalVariable"> FinalLocalVariable</a></li>
<li><a href="#HiddenField"> HiddenField</a></li>
<li><a href="#IllegalInstantiation"> IllegalInstantiation</a></li>
<li><a href="#IllegalToken"> IllegalToken</a></li>
<li><a href="#IllegalTokenText"> IllegalTokenText</a></li>
<li><a href="#InnerAssignment"> InnerAssignment</a></li>
<li><a href="#MagicNumber"> MagicNumber</a></li>
<li><a href="#MissingSwitchDefault"> MissingSwitchDefault</a></li>
<li><a href="#ModifiedControlVariable"> ModifiedControlVariable</a></li>
<li><a href="#RedundantThrows"> RedundantThrows</a></li>
<li><a href="#SimplifyBooleanExpression"> SimplifyBooleanExpression</a></li>
<li><a href="#SimplifyBooleanReturn"> SimplifyBooleanReturn</a></li>
<li><a href="#StringLiteralEquality"> StringLiteralEquality</a></li>
<li><a href="#NestedIfDepth"> NestedIfDepth</a></li>
<li><a href="#NestedTryDepth"> NestedTryDepth</a></li>
<li><a href="#SuperClone"> SuperClone</a></li>
<li><a href="#SuperFinalize"> SuperFinalize</a></li>
<li><a href="#IllegalCatch"> IllegalCatch</a></li>
<li><a href="#IllegalThrows"> IllegalThrows</a></li>
<li><a href="#PackageDeclaration"> PackageDeclaration</a></li>
<li><a href="#JUnitTestCase"> JUnitTestCase</a></li>
<li><a href="#ReturnCount"> ReturnCount</a></li>
<li><a href="#IllegalType"> IllegalType</a></li>
<li><a href="#DeclarationOrder"> DeclarationOrder</a></li>
<li><a href="#ParameterAssignment"> ParameterAssignment</a></li>
<li><a href="#ExplicitInitialization"> ExplicitInitialization</a></li>
<li><a href="#DefaultComesLast"> DefaultComesLast</a></li>
<li><a href="#MissingCtor"> MissingCtor</a></li>
<li><a href="#FallThrough"> FallThrough</a></li>
<li><a href="#MultipleStringLiterals"> MultipleStringLiterals</a></li>
<li><a href="#MultipleVariableDeclarations"> MultipleVariableDeclarations</a></li>
<li><a href="#RequireThis"> RequireThis</a></li>
<li><a href="#UnnecessaryParentheses"> UnnecessaryParentheses</a></li>
<li> <a href="./config_design.html"> Class Design</a>
</li>
<li> <a href="./config_duplicates.html"> Duplicate Code</a>
</li>
<li> <a href="./config_metrics.html"> Metrics</a>
</li>
<li> <a href="./config_misc.html"> Miscellaneous</a>
</li>
<li> <a href="./optional.html">Optional Checks</a>
</li>
<li> <a href="./config_j2ee.html"> J2EE Checks</a>
</li>
<li> <a href="./extending.html">Extending Checkstyle</a>
</li>
<li> <a href="./writingchecks.html"> Writing checks</a>
</li>
<li> <a href="./writingfilters.html"> Writing filters</a>
</li>
<li> <a href="./writinglisteners.html"> Writing listeners</a>
</li>
<li> <a href="./api/index.html">Javadoc</a>
</li>
<li>
<strong>SourceForge</strong>
</li>
<li> <a href="http://sourceforge.net/mail/?group_id=29721">Mailing Lists</a>
</li>
<li> <a href="http://sourceforge.net/tracker/?atid=397078&group_id=29721&func=browse">Bug Database</a>
</li>
<li> <a href="http://sourceforge.net/tracker/?atid=397081&group_id=29721&func=browse">Feature Requests</a>
</li>
<li>
<strong>Developers</strong>
</li>
<li> <a href="http://sourceforge.net/projects/checkstyle">Project Page</a>
</li>
<li> <a href="http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/checkstyle/">CVS Repository</a>
</li>
<li> <a href="./contributing.html">Contributing</a>
</li>
</ul>
<ul>
<li>
<strong>Hosted by:</strong>
<div align="center">
<p><a href="http://sourceforge.net">
<img src="http://sourceforge.net/sflogo.php?group_id=29721&type=1" width="88" height="31" alt="SourceForge Logo"/></a>
</p>
</div>
</li>
</ul>
<!-- end makeNavigationBar -->
<!-- ============================================================ -->
</div>
</div>
<div class="csMain">
<a id="ArrayTrailingComma"></a>
<h2>ArrayTrailingComma</h2>
<h3>Description</h3>
<p>
Checks that array initialization contains a trailing comma.
</p>
<div align="left">
<table cellspacing="4" cellpadding="0" border="0">
<tr>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
<tr>
<td bgcolor="#023264" width="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#ffffff"><pre>int[] a = new int[]
{
1,
2,
3,
};</pre></td>
<td bgcolor="#023264" width="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
<tr>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
</table>
</div>
<p>
The check allows to not add a comma if both left and right curlys
are on the same line.
</p>
<div align="left">
<table cellspacing="4" cellpadding="0" border="0">
<tr>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
<tr>
<td bgcolor="#023264" width="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#ffffff"><pre>return new int[] { 0 };</pre></td>
<td bgcolor="#023264" width="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
<tr>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
</table>
</div>
<p>
Rationale: Putting this comma in makes it easier to change the order
of the elements or add new elements on the end.
</p>
<h3>Examples</h3>
<p>
To configure the check:
</p>
<div align="left">
<table cellspacing="4" cellpadding="0" border="0">
<tr>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
<tr>
<td bgcolor="#023264" width="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#ffffff"><pre><module name="ArrayTrailingComma"/></pre></td>
<td bgcolor="#023264" width="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
<tr>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
</table>
</div>
<h3>Package</h3>
<p>
com.puppycrawl.tools.checkstyle.checks.coding
</p>
<h3>Parent Module</h3>
<p>
<a href="config.html#treewalker">TreeWalker</a>
</p>
<a id="AvoidInlineConditionals"></a>
<h2>AvoidInlineConditionals</h2>
<h3>Description</h3>
<p>
Detects inline conditionals. An example inline conditional is this:
</p>
<div align="left">
<table cellspacing="4" cellpadding="0" border="0">
<tr>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
<tr>
<td bgcolor="#023264" width="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#ffffff"><pre>String a = getParameter("a");
String b = (a==null || a.length<1) ? null : a.substring(1);</pre></td>
<td bgcolor="#023264" width="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
<tr>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
</table>
</div>
<p>
Rationale: Some developers find inline conditionals hard to read, so
their company's coding standards forbids them.
</p>
<h3>Examples</h3>
<p>
To configure the check:
</p>
<div align="left">
<table cellspacing="4" cellpadding="0" border="0">
<tr>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
<tr>
<td bgcolor="#023264" width="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#ffffff"><pre><module name="AvoidInlineConditionals"/></pre></td>
<td bgcolor="#023264" width="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
<tr>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
</table>
</div>
<h3>Package</h3>
<p>
com.puppycrawl.tools.checkstyle.checks.coding
</p>
<h3>Parent Module</h3>
<p>
<a href="config.html#treewalker">TreeWalker</a>
</p>
<a id="CovariantEquals"></a>
<h2>CovariantEquals</h2>
<h3>Description</h3>
<p>
Checks that classes that define a covariant <span class="code">equals()</span> method also override method <span class="code">equals(java.lang.Object)</span>. Inspired by <a href="http://www.cs.umd.edu/~pugh/java/bugs/docs/findbugsPaper.pdf">findbugs</a>.
</p>
<p>
Rationale: Mistakenly defining a covariant <span class="code">equals()</span> method without overriding method <span class="code">equals(java.lang.Object)</span> can produce unexpected
runtime behaviour.
</p>
<h3>Example</h3>
<p>
To configure the check:
</p>
<div align="left">
<table cellspacing="4" cellpadding="0" border="0">
<tr>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
<tr>
<td bgcolor="#023264" width="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#ffffff"><pre><module name="CovariantEquals"/></pre></td>
<td bgcolor="#023264" width="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
<tr>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
</table>
</div>
<h3>Package</h3>
<p>
com.puppycrawl.tools.checkstyle.checks.coding
</p>
<h3>Parent Module</h3>
<p>
<a href="config.html#treewalker">TreeWalker</a>
</p>
<a id="DoubleCheckedLocking"></a>
<h2>DoubleCheckedLocking</h2>
<h3>Description</h3>
<p>
The "double-checked locking" idiom (DCL) tries to avoid
the runtime cost of synchronization. An example that uses the DCL
idiom is this:
</p>
<div align="left">
<table cellspacing="4" cellpadding="0" border="0">
<tr>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
<tr>
<td bgcolor="#023264" width="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#ffffff"><pre>public class MySingleton
{
private static theInstance = null;
private MySingleton() {}
public MySingleton getInstance() {
if ( theInstance == null ) { // synchronize only if necessary
synchronized( MySingleton.class ) {
if ( theInstance == null ) {
theInstance = new MySingleton();
}
}
}
}
}</pre></td>
<td bgcolor="#023264" width="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
<tr>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
</table>
</div>
<p>
The problem with the DCL idiom in Java is that it just does not work
correctly. Using it introduces bugs that are extremely hard to
track down and reproduce. The <a href="http://www.cs.umd.edu/~pugh/java/memoryModel/DoubleCheckedLocking.html">
"Double-Checked Locking is Broken" Declaration</a> has an
in depth explanation of the exact problem which has to do with the
semantics of the Java memory model.
</p>
<p>
The DoubleCheckedLocking check will find source code where a test is
wrapped in a synchronized block that is wrapped in the same test,
like in the example above.
</p>
<h3>Examples</h3>
<p>
To configure the check:
</p>
<div align="left">
<table cellspacing="4" cellpadding="0" border="0">
<tr>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
<tr>
<td bgcolor="#023264" width="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#ffffff"><pre><module name="DoubleCheckedLocking"/></pre></td>
<td bgcolor="#023264" width="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
<tr>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
</table>
</div>
<h3>Package</h3>
<p>
com.puppycrawl.tools.checkstyle.checks.coding
</p>
<h3>Parent Module</h3>
<p>
<a href="config.html#treewalker">TreeWalker</a>
</p>
<a id="EmptyStatement"></a>
<h2>EmptyStatement</h2>
<h3>Description</h3>
<p>
Detects empty statements (standalone ;).
</p>
<h3>Examples</h3>
<p>
To configure the check:
</p>
<div align="left">
<table cellspacing="4" cellpadding="0" border="0">
<tr>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
<tr>
<td bgcolor="#023264" width="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#ffffff"><pre><module name="EmptyStatement"/></pre></td>
<td bgcolor="#023264" width="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
<tr>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
</table>
</div>
<h3>Package</h3>
<p>
com.puppycrawl.tools.checkstyle.checks.coding
</p>
<h3>Parent Module</h3>
<p>
<a href="config.html#treewalker">TreeWalker</a>
</p>
<a id="EqualsHashCode"></a>
<h2>EqualsHashCode</h2>
<h3>Description</h3>
<p>
Checks that classes that override <span class="code">equals()</span>
also override <span class="code">hashCode()</span>.
</p>
<p>
Rationale: The contract of <span class="code">equals()</span> and
<span class="code"> hashCode()</span> requires that equal objects
have the same hashCode. Hence, whenever you override <span class="code">equals()</span> you must override <span class="code">
hashCode()</span> to ensure that your class can be used in
collections that are hash based.
</p>
<h3>Example</h3>
<p>
To configure the check:
</p>
<div align="left">
<table cellspacing="4" cellpadding="0" border="0">
<tr>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
<tr>
<td bgcolor="#023264" width="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#ffffff"><pre><module name="EqualsHashCode"/></pre></td>
<td bgcolor="#023264" width="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
<tr>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
</table>
</div>
<h3>Package</h3>
<p>
com.puppycrawl.tools.checkstyle.checks.coding
</p>
<h3>Parent Module</h3>
<p>
<a href="config.html#treewalker">TreeWalker</a>
</p>
<a id="FinalLocalVariable"></a>
<h2>FinalLocalVariable</h2>
<h3>Description</h3>
<p>
Checks that local variables that never have their values changed are
declared final. The check can be configured to also check that
unchanged parameters are declared final.
</p>
<h3>Notes</h3>
<p>
When configured to check parameters, the check ignores parameters of
interface methods and abstract methods.
</p>
<h3>Properties</h3>
<table>
<tr class="even">
<th valign="top" align="left"
>
name
</th>
<th valign="top" align="left"
>
description
</th>
<th valign="top" align="left"
>
type
</th>
<th valign="top" align="left"
>
default value
</th>
</tr>
<tr class="odd">
<td class="odd"
>
tokens
</td>
<td class="odd"
>
tokens to check
</td>
<td class="odd"
>
subset of tokens <a href="api/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#PARAMETER_DEF">PARAMETER_DEF</a>,
<a href="api/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#VARIABLE_DEF">VARIABLE_DEF</a>
</td>
<td class="odd"
>
<a href="api/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#VARIABLE_DEF">VARIABLE_DEF</a>
</td>
</tr>
</table>
<h3>Examples</h3>
<p>
To configure the check:
</p>
<div align="left">
<table cellspacing="4" cellpadding="0" border="0">
<tr>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
<tr>
<td bgcolor="#023264" width="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#ffffff"><pre><module name="FinalLocalVariable"/></pre></td>
<td bgcolor="#023264" width="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
<tr>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
</table>
</div>
<p>
To configure the check so that it checks local variables and
parameters:
</p>
<div align="left">
<table cellspacing="4" cellpadding="0" border="0">
<tr>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
<tr>
<td bgcolor="#023264" width="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#ffffff"><pre><module name="FinalLocalVariable">
<property name="tokens" value="VARIABLE_DEF,PARAMETER_DEF"/>
</module></pre></td>
<td bgcolor="#023264" width="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
<tr>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
</table>
</div>
<h3>Package</h3>
<p>
com.puppycrawl.tools.checkstyle.checks.coding
</p>
<h3>Parent Module</h3>
<p>
<a href="config.html#treewalker">TreeWalker</a>
</p>
<a id="HiddenField"></a>
<h2>HiddenField</h2>
<h3>Description</h3>
<p>
Checks that a local variable or a parameter does not shadow a field
that is defined in the same class.
</p>
<h3>Properties</h3>
<table>
<tr class="even">
<th valign="top" align="left"
>
name
</th>
<th valign="top" align="left"
>
description
</th>
<th valign="top" align="left"
>
type
</th>
<th valign="top" align="left"
>
default value
</th>
</tr>
<tr class="odd">
<td class="odd"
>
tokens
</td>
<td class="odd"
>
tokens to check
</td>
<td class="odd"
>
subset of tokens <a href="api/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#PARAMETER_DEF">PARAMETER_DEF</a>,
<a href="api/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#VARIABLE_DEF">VARIABLE_DEF</a>
</td>
<td class="odd"
>
<a href="api/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#PARAMETER_DEF">PARAMETER_DEF</a>,
<a href="api/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#VARIABLE_DEF">VARIABLE_DEF</a>
</td>
</tr>
<tr class="even">
<td class="even"
>
ignoreFormat
</td>
<td class="even"
>
pattern for names to ignore
</td>
<td class="even"
>
<a href="property_types.html#regexp">regular expression</a>
</td>
<td class="even"
>
(not applied)
</td>
</tr>
<tr class="odd">
<td class="odd"
>
ignoreConstructorParameter
</td>
<td class="odd"
>
Controls whether to ignore constructor parameters.
</td>
<td class="odd"
>
<a href="property_types.html#boolean">Boolean</a>
</td>
<td class="odd"
>
<span class="default">false</span>
</td>
</tr>
<tr class="even">
<td class="even"
>
ignoreSetter
</td>
<td class="even"
>
Controls whether to ignore the parameter of a property setter
method, where the property setter method for field
"xyz" has name "setXyz", one parameter named
"xyz", and return type <span class="code">void</span>.
</td>
<td class="even"
>
<a href="property_types.html#boolean">Boolean</a>
</td>
<td class="even"
>
<span class="default">false</span>
</td>
</tr>
<tr class="odd">
<td class="odd"
>
ignoreAbstractMethods
</td>
<td class="odd"
>
Controls whether to ignore parameters of abstract methods.
</td>
<td class="odd"
>
<a href="property_types.html#boolean">Boolean</a>
</td>
<td class="odd"
>
<span class="default">false</span>
</td>
</tr>
</table>
<h3>Examples</h3>
<p>
To configure the check:
</p>
<div align="left">
<table cellspacing="4" cellpadding="0" border="0">
<tr>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
<tr>
<td bgcolor="#023264" width="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#ffffff"><pre><module name="HiddenField"/></pre></td>
<td bgcolor="#023264" width="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
<tr>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
</table>
</div>
<p>
To configure the check so that it checks local variables but not
parameters:
</p>
<div align="left">
<table cellspacing="4" cellpadding="0" border="0">
<tr>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
<tr>
<td bgcolor="#023264" width="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#ffffff"><pre><module name="HiddenField">
<property name="tokens" value="VARIABLE_DEF"/>
</module></pre></td>
<td bgcolor="#023264" width="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
<tr>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
</table>
</div>
<p>
To configure the check so that it ignores the name
"rcsid":
</p>
<div align="left">
<table cellspacing="4" cellpadding="0" border="0">
<tr>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
<tr>
<td bgcolor="#023264" width="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#ffffff"><pre><module name="HiddenField">
<property name="ignoreFormat" value="^rcsid$"/>
</module></pre></td>
<td bgcolor="#023264" width="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
<tr>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
</table>
</div>
<p>
To configure the check so that it ignores constructor parameters:
</p>
<div align="left">
<table cellspacing="4" cellpadding="0" border="0">
<tr>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
<tr>
<td bgcolor="#023264" width="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#ffffff"><pre><module name="HiddenField">
<property name="ignoreConstructorParameter" value="true"/>
</module></pre></td>
<td bgcolor="#023264" width="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
<tr>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
</table>
</div>
<p>
To configure the check so that it ignores the parameter of setter
methods:
</p>
<div align="left">
<table cellspacing="4" cellpadding="0" border="0">
<tr>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
<tr>
<td bgcolor="#023264" width="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#ffffff"><pre><module name="HiddenField">
<property name="ignoreSetter" value="true"/>
</module></pre></td>
<td bgcolor="#023264" width="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
<tr>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
<td bgcolor="#023264" width="1" height="1"><img src="/images/void.gif" width="1" height="1" vspace="0" hspace="0" border="0"/></td>
</tr>
</table>
</div>
<h3>Package</h3>
<p>
com.puppycrawl.tools.checkstyle.checks.coding
</p>
<h3>Parent Module</h3>
<p>
<a href="config.html#treewalker">TreeWalker</a>
</p>
<a id="IllegalInstantiation"></a>
<h2>IllegalInstantiation</h2>
<h3>Description</h3>
<p>
Checks for illegal instantiations where a factory method is
preferred.
</p>
<p>
Rationale: Depending on the project, for some classes it might be
preferable to create instances through factory methods rather than
calling the constructor.
</p>
<p>
A simple example is the <span class="code">java.lang.Boolean</span>
class. In order to save memory and CPU cycles, it is preferable to
use the predefined constants <span class="code"> TRUE</span> and
<span class="code">FALSE</span>. Constructor invocations should be
replaced by calls to <span class="code">Boolean.valueOf()</span>.
</p>
<p>
Some extremely performance sensitive projects may require the use of
factory methods for other classes as well, to enforce the usage of
number caches or object pools.
</p>
<h3>Notes</h3>
<p>
There is a limitation that it is currently not possible to specify
array classes.
</p>
<h3>Properties</h3>
<table>
<tr class="even">
<th valign="top" align="left"
>
name
</th>
<th valign="top" align="left"
>