checkstyle.xml

<?xml version="1.0"?>
<!DOCTYPE module PUBLIC "-//Puppy Crawl//DTD Check Configuration 1.2//EN" "http://www.puppycrawl.com/dtds/configuration_1_2.dtd">
<module name="Checker">
  <module name="NewlineAtEndOfFile">
    <property name="lineSeparator" value="lf"/>
  </module>
  <!-- Trailing spaces -->
  <module name="RegexpSingleline">
    <property name="format" value="\s+$"/>
    <property name="message" value="Line has trailing spaces."/>
  </module>

  <!-- Checks for the new line format -->
  <module name="RegexpMultiline">
    <property name="format" value="\r\n"/>
    <property name="message" value="Do not use Windows line endings"/>
  </module>

  <module name="TreeWalker">
    <module name="RegexpSinglelineJava">
      <property name="format" value="^\t* "/>
      <property name="message" value="Indent must use tab characters"/>
      <property name="ignoreComments" value="true"/>
    </module>

    <!-- Checks for imports                              -->
    <!-- See http://checkstyle.sf.net/config_import.html -->
    <module name="AvoidStarImport"/>
    <module name="IllegalImport"/> <!-- defaults to sun.* packages -->
    <module name="RedundantImport"/>
    <module name="UnusedImports">
      <property name="processJavadoc" value="true"/>
    </module>

    <!-- Checks for whitespace                               -->
    <!-- See http://checkstyle.sf.net/config_whitespace.html -->
    <module name="GenericWhitespace"/>
    <module name="EmptyForIteratorPad"/>
    <module name="MethodParamPad"/>
    <module name="NoWhitespaceAfter">
      <property name="tokens" value="BNOT, DEC, DOT, INC, LNOT, UNARY_MINUS, UNARY_PLUS"/>
    </module>
    <module name="NoWhitespaceBefore"/>
    <module name="OperatorWrap"/>
    <module name="ParenPad"/>
    <module name="WhitespaceAfter"/>
    <module name="WhitespaceAround"/>

    <!-- Modifier Checks                                    -->
    <!-- See http://checkstyle.sf.net/config_modifiers.html -->
    <module name="ModifierOrder"/>
    <module name="RedundantModifier"/>

    <!-- Checks for blocks. You know, those {}'s         -->
    <!-- See http://checkstyle.sf.net/config_blocks.html -->
    <module name="LeftCurly" />
    <module name="RightCurly" />
    <module name="NeedBraces"/>

    <!-- Checks for class design                         -->
    <!-- See http://checkstyle.sf.net/config_design.html -->
    <module name="InterfaceIsType"/>
    <module name="HideUtilityClassConstructor"/>
  </module>
</module>