checkstyle.xml

<?xml version="1.0"?>
<!DOCTYPE module PUBLIC
    "-//Checkstyle//DTD Checkstyle Configuration 1.3//EN"
    "https://checkstyle.org/dtds/configuration_1_3.dtd">

<module name = "Checker">
  <property name="charset" value="UTF-8"/>

  <property name="severity" value="error"/>

  <property name="fileExtensions" value="java, properties, xml"/>
  <!-- Checks for whitespace                               -->
  <!-- See http://checkstyle.sf.net/config_whitespace.html -->
  <module name="FileTabCharacter">
    <property name="eachLine" value="true"/>
  </module>
  <module name="LineLength">
    <property name="max" value="110"/>
    <property name="ignorePattern" value="^package.*|^import.*|a href|href|http://|https://|ftp://"/>
  </module>

  <module name="TreeWalker">
    <module name="FinalLocalVariable"/>

    <!-- Required by SuppressWarningsFilter below -->
    <module name="SuppressWarningsHolder"/>

    <!-- Allow turning checks off in the code -->
    <!-- See http://checkstyle.sourceforge.net/config.html#SuppressionCommentFilter -->
    <module name="SuppressionCommentFilter"/>
  </module>

  <!-- Allow turning checks off in the code using @SuppressWarnings annotation -->
  <!-- See http://checkstyle.sourceforge.net/config_filters.html#SuppressWarningsFilter -->
  <module name="SuppressWarningsFilter"/>

  <!-- Location is overridable in a project. For mechanism, see -->
  <!-- http://checkstyle.sourceforge.net/config_filters.html#SuppressionFilter -->
  <module name="SuppressionFilter">
    <property name="file" value="suppressions.xml"/>
    <property name="optional" value="true"/>
  </module>
</module>