code: ///////////////////////////////////////////////////////////////////////////////////////////////
  // checkstyle: Checks Java source code and other text files for adherence to a set of rules.
  // Copyright (C) 2001-2023 the original author or authors.
  //
  // This library is free software; you can redistribute it and/or
  // modify it under the terms of the GNU Lesser General Public
  // License as published by the Free Software Foundation; either
  // version 2.1 of the License, or (at your option) any later version.
  //
  // This library is distributed in the hope that it will be useful,
  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  // Lesser General Public License for more details.
  //
  // You should have received a copy of the GNU Lesser General Public
  // License along with this library; if not, write to the Free Software
  // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  ///////////////////////////////////////////////////////////////////////////////////////////////
  
  package com.puppycrawl.tools.checkstyle.checks.javadoc;
  
  import com.puppycrawl.tools.checkstyle.StatelessCheck;
  import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
  import com.puppycrawl.tools.checkstyle.api.DetailAST;
  import com.puppycrawl.tools.checkstyle.api.TokenTypes;
  import com.puppycrawl.tools.checkstyle.utils.JavadocUtil;
  
  /**
   * <p>
   * Checks that Javadocs are located at the correct position. As specified at
   * <a href="https://docs.oracle.com/en/java/javase/11/docs/specs/doc-comment-spec.html">
   * Documentation Comment Specification for the Standard Doclet</a>, Javadocs are recognized
   * only when placed immediately before module, package, class, interface,
   * constructor, method, or field declarations. Any other position, like in the
   * body of a method, will be ignored by the javadoc tool and is considered
   * invalid by this check.
   * </p>
   * <p>
   * To configure the check:
   * </p>
   * <pre>
   * &lt;module name="InvalidJavadocPosition"/&gt;
   * </pre>
   * <p>
   * The following code produces a violation because Javadocs should be before all annotations of
   * the Javadoc's target:
   * </p>
   * <pre>
   * &#064;SuppressWarnings("serial")
   * /**
   *  * This comment looks like javadoc but it at an invalid location.
   *  * Therefore, the text will not get into TestClass.html and the check will produce a violation.
   *  *&#47;
   * public class TestClass {
   * }
   * </pre>
   * <p>
   * Parent is {@code com.puppycrawl.tools.checkstyle.TreeWalker}
   * </p>
   * <p>
   * Violation Message Keys:
   * </p>
   * <ul>
   * <li>
   * {@code invalid.position}
   * </li>
   * </ul>
   *
   * @since 8.23
   */
  @StatelessCheck
  public class InvalidJavadocPositionCheck extends AbstractCheck {
  
      /**
       * A key is pointing to the warning message text in "messages.properties"
       * file.
       */
      public static final String MSG_KEY = "invalid.position";
  
      @Override
      public int[] getDefaultTokens() {
          return new int[] {
              TokenTypes.BLOCK_COMMENT_BEGIN,
          };
      }
  
      @Override
      public int[] getAcceptableTokens() {
          return getDefaultTokens();
      }
  
      @Override
      public int[] getRequiredTokens() {
          return getDefaultTokens();
      }
  
      @Override
      public boolean isCommentNodesRequired() {
          return true;
      }
  
      @Override
      public void visitToken(DetailAST ast) {
          final String commentContent = JavadocUtil.getBlockCommentContent(ast);
  
          if (JavadocUtil.isJavadocComment(commentContent)
                  && !JavadocUtil.isCorrectJavadocPosition(ast)) {
              log(ast, MSG_KEY);
          }
      }
  
  }
  