src/conf/checkstyle.xml

<?xml version="1.0"?>
<!--
Licensed to the Apache Software Foundation (ASF) under one or more
contributor license agreements.  See the NOTICE file distributed with
this work for additional information regarding copyright ownership.
The ASF licenses this file to You under the Apache License, Version 2.0
(the "License"); you may not use this file except in compliance with
the License.  You may obtain a copy of the License at

     https://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
-->
<!DOCTYPE module PUBLIC
    "-//Checkstyle//DTD Checkstyle Configuration 1.3//EN"
    "https://checkstyle.org/dtds/configuration_1_3.dtd">
<module name="Checker">
  <module name="FileTabCharacter">
    <property name="fileExtensions" value="java" />
  </module>
  <module name="Header">
    <property name="headerFile" value="${checkstyle.header.file}" />
  </module>
  <module name="JavadocPackage" />
  <module name="LineLength">
      <!-- Ignore lines that begin with " * ", such as within a Javadoc comment. -->
      <property name="ignorePattern" value="^ *\* *[^ ]"/>
      <property name="max" value="160"/>
  </module>
  <module name="NewlineAtEndOfFile" />
  <module name="RegexpSingleline">
    <property name="format" value="\s+$" />
    <property name="message" value="Line has trailing spaces." />
    <property name="fileExtensions" value="java" />
  </module>
  <!-- @author tags are deprecated -->
  <module name="RegexpSingleline">
    <property name="format" value="^\s+\*\s+@author\s" />
    <property name="message" value="Deprecated @author tag" />
    <property name="fileExtensions" value="java" />
    <property name="severity" value="warning" />
  </module>
  <module name="SuppressionFilter">
    <property name="file" value="src/conf/checkstyle-suppressions.xml"/>
  </module>
  <module name="TreeWalker">
    <module name="ArrayTypeStyle" />
    <module name="AvoidStarImport" />
    <module name="CovariantEquals" />
    <module name="DefaultComesLast" />
    <module name="EmptyBlock">
      <property name="option" value="text" />
    </module>
    <module name="EqualsHashCode" />
    <module name="ExplicitInitialization" />
    <module name="FallThrough" />
    <module name="FinalLocalVariable" />
    <module name="IllegalImport" />
    <module name="IllegalInstantiation" />
    <module name="ImportOrder">
      <property name="option" value="top" />
      <property name="groups" value="java,javax,org" />
      <property name="ordered" value="true" />
      <property name="separated" value="true" />
    </module>
    <module name="LeftCurly" />
    <module name="MissingOverride" />
    <module name="ModifierOrder" />
    <module name="NeedBraces" />
    <module name="OperatorWrap">
      <property name="option" value="eol" />
    </module>
    <module name="ParenPad" />
    <module name="RedundantImport" />
    <module name="RedundantModifier" />
    <module name="RightCurly" />
    <module name="SimplifyBooleanExpression" />
    <module name="SimplifyBooleanReturn" />
    <module name="StringLiteralEquality" />
    <module name="SuperClone" />
    <module name="SuperFinalize" />
    <module name="TypecastParenPad" />    
    <module name="UnnecessaryParentheses" />
    <module name="UnusedImports" />
    <module name="UpperEll" />
    <module name="WhitespaceAfter" />
    <module name="WhitespaceAround" />
  </module>
  <property name="localeLanguage" value="en" />
</module>