checkstyle-config.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">

  <!-- no explicit TAB characters in source code plz (set editor to use spaces) -->
  <module name="FileTabCharacter"/>

  <module name="TreeWalker">
    <!-- Enforce standard Java field, class, method naming conventions -->
    <module name="ConstantName" />
    <module name="LocalFinalVariableName" />
    <module name="LocalVariableName" />
    <module name="MethodName" />
    <module name="MemberName" />
    <module name="TypeName" />
    <module name="StaticVariableName" />

    <!-- no import org.whoever.* -->
    <!-- <module name="AvoidStarImport" /> -->

    <!-- Don't allow most kinds of empty blocks -->
    <module name="EmptyBlock">
      <!-- empty blocks for catch and instance init are allowed -->
      <property name="tokens" value="LITERAL_DO,LITERAL_ELSE,LITERAL_FINALLY,LITERAL_IF,LITERAL_FOR,LITERAL_TRY,LITERAL_WHILE" />
    </module>

    <!-- left curl braces at EOL of block declaration stmt, max line len 120 chars -->
  <!--
    <module name="LeftCurly">
      <property name="maxLineLength" value="120" />
    </module>
  -->

    <!-- line length; start gentle and tighten this up later perhaps -->
  <!--
    <module name="LineLength">
      <property name="max" value="120" />
    </module>
  -->

    <!-- Java Generic param decls do not require whitespace inside of angle brackets -->
    <module name="GenericWhitespace" />

    <!-- no whitespace just after enter or before exit parens block i.e. if (good != bad) { ... } -->
    <module name="ParenPad" />

    <!-- Use whitespace after paren-based typecase, semicolon, or comma unless at EOL -->
    <module name="WhitespaceAfter" />

    <!-- Use whitespace around typical tokens like = sign. Empty method/class decl should use { } and so on -->
    <module name="WhitespaceAround" />

    <!-- stmts that form blocks need to use curlies always (like if..else) -->
    <!-- <module name="NeedBraces" /> -->

    <!-- anonymous non-static blocks inline should be avoided and are often cut/paste/debug errors -->
    <module name="AvoidNestedBlocks" />

    <!-- Utility classes w/all-static methods should not have public ctors -->
    <module name="HideUtilityClassConstructor" />

    <!-- defining an equals() method w/o Overriding Object#equals properly will give you master course in debugging -->
    <module name="CovariantEquals" />

    <!-- ALWAYS override Object#hashCode when you override Object#equals and vice versa -->
    <module name="EqualsHashCode" />

    <!-- Warn us when same-name declarations shadow decl's from the enclosing scope -->
    <module name="HiddenField">
      <property name="tokens" value="VARIABLE_DEF" />
      <property name="ignoreConstructorParameter" value="true" />
      <property name="ignoreSetter" value="true" />
    </module>

    <!-- Make sure all switch stmts have a matching default case at the end of the switch block -->
    <module name="MissingSwitchDefault" />
    <module name="DefaultComesLast" />

    <!-- make sure the index of a for loop is not modified inside that loop -->
    <module name="ModifiedControlVariable" />

    <!-- all Java string equality must be checked with Object#equals not == -->
    <module name="StringLiteralEquality" />

    <!-- Avoid nested for loops beyond depth 3, O(n^3) is shitty enough -->
    <module name="NestedForDepth">
      <property name="max" value="3" />
    </module>

    <!-- Don't every use/modify Object#clone its basically broken in Java -->
    <module name="NoClone" />

    <!-- if class overrides finalize() (better be good reason) then better call super.finalize() -->
    <module name="SuperFinalize" />

    <!-- Make sure every java class is declared in an associated package, you can't import top-level class decls -->
    <module name="PackageDeclaration" />

    <!-- Java declaration order for classes: static fields, fields, ctor, methods -->
    <!-- <module name="DeclarationOrder" /> -->

    <!-- ensure that all casse fall-throughs that aren't marked /* fallthru */ on the next case stmt warn us -->
    <!-- <module name="FallThrough" /> -->

    <!-- Only allow 1 occurance of a String literal without warning (should just use constant at that point) -->
  <!--
    <module name="MultipleStringLiterals">
      <property name="ignoreStringsRegexp" value='^(("")|(", ")|("\t")|("\n"))$' />
    </module>
  -->

    <!-- one variable decl per line/stmt -->
    <module name="MultipleVariableDeclarations" />

    <!-- get rid of extra parens without risking pilot error -->
    <!-- <module name="UnnecessaryParentheses"/> -->

    <!-- one stmt per line -->
    <module name="OneStatementPerLine"/>

    <!-- no redundant import stmts -->
    <module name="RedundantImport"/>

    <!-- don't import classes that are never used in the code -->
    <module name="UnusedImports">
      <property name="processJavadoc" value="false" />
    </module>

    <!-- Warns on stray TODO: 's so that we can track leftover tasks etc. -->
    <!-- <module name="TodoComment" /> -->

    <!-- Java will do dumb stuff if you aren't explicit: 0 == int, 0L == long, 0l == confusing -->
    <module name="UpperEll"/>

    <!-- normalize our code indentation at 2 or 0 spaces -->
    <!--  * GENERATES MANY WARNINGS (10k+) *
    <module name="Indentation">
      <property name="basicOffset" value="2" />
      <property name="caseIndent" value="0" />
      <property name="braceAdjustment" value="0" />
      <property name="throwsIndent" value="2" />
    </module>
    -->

    <!-- Outermost type declaration and Java file name must match -->
    <module name="OuterTypeFilename"/>

    <!-- Java interfaces always have public static final fields and public methods -->
    <!-- <module name="RedundantModifier"/> -->

  </module> <!-- END TreeWalker -->

</module> <!-- END Checker -->

  <!-- TEMPLATE PARAMETERIZED CHECK
    <module name="">
      <property name="" value="" />
    </module>
  -->