code: /*
   * Copyright (c) 1995, 2011, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.  Oracle designates this
   * particular file as subject to the "Classpath" exception as provided
   * by Oracle in the LICENSE file that accompanied this code.
   *
   * This code 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 General Public License
   * version 2 for more details (a copy is included in the LICENSE file that
   * accompanied this code).
   *
   * You should have received a copy of the GNU General Public License version
   * 2 along with this work; if not, write to the Free Software Foundation,
   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
   * or visit www.oracle.com if you need additional information or have any
   * questions.
   */
  
  package java.lang;
  
  /**
   * An {@code Error} is a subclass of {@code Throwable}
   * that indicates serious problems that a reasonable application
   * should not try to catch. Most such errors are abnormal conditions.
   * The {@code ThreadDeath} error, though a "normal" condition,
   * is also a subclass of {@code Error} because most applications
   * should not try to catch it.
   * <p>
   * A method is not required to declare in its {@code throws}
   * clause any subclasses of {@code Error} that might be thrown
   * during the execution of the method but not caught, since these
   * errors are abnormal conditions that should never occur.
   *
   * That is, {@code Error} and its subclasses are regarded as unchecked
   * exceptions for the purposes of compile-time checking of exceptions.
   *
   * @author  Frank Yellin
   * @see     java.lang.ThreadDeath
   * @jls 11.2 Compile-Time Checking of Exceptions
   * @since   JDK1.0
   */
  public class Error extends Throwable {
      static final long serialVersionUID = 4980196508277280342L;
  
      /**
       * Constructs a new error with {@code null} as its detail message.
       * The cause is not initialized, and may subsequently be initialized by a
       * call to {@link #initCause}.
       */
      public Error() {
          super();
      }
  
      /**
       * Constructs a new error with the specified detail message.  The
       * cause is not initialized, and may subsequently be initialized by
       * a call to {@link #initCause}.
       *
       * @param   message   the detail message. The detail message is saved for
       *          later retrieval by the {@link #getMessage()} method.
       */
      public Error(String message) {
          super(message);
      }
  
      /**
       * Constructs a new error with the specified detail message and
       * cause.  <p>Note that the detail message associated with
       * {@code cause} is <i>not</i> automatically incorporated in
       * this error's detail message.
       *
       * @param  message the detail message (which is saved for later retrieval
       *         by the {@link #getMessage()} method).
       * @param  cause the cause (which is saved for later retrieval by the
       *         {@link #getCause()} method).  (A {@code null} value is
       *         permitted, and indicates that the cause is nonexistent or
       *         unknown.)
       * @since  1.4
       */
      public Error(String message, Throwable cause) {
          super(message, cause);
      }
  
      /**
       * Constructs a new error with the specified cause and a detail
       * message of {@code (cause==null ? null : cause.toString())} (which
       * typically contains the class and detail message of {@code cause}).
       * This constructor is useful for errors that are little more than
       * wrappers for other throwables.
       *
       * @param  cause the cause (which is saved for later retrieval by the
       *         {@link #getCause()} method).  (A {@code null} value is
       *         permitted, and indicates that the cause is nonexistent or
       *         unknown.)
       * @since  1.4
       */
      public Error(Throwable cause) {
          super(cause);
      }
  
      /**
       * Constructs a new error with the specified detail message,
       * cause, suppression enabled or disabled, and writable stack
       * trace enabled or disabled.
       *
       * @param  message the detail message.
       * @param cause the cause.  (A {@code null} value is permitted,
       * and indicates that the cause is nonexistent or unknown.)
       * @param enableSuppression whether or not suppression is enabled
       *                          or disabled
       * @param writableStackTrace whether or not the stack trace should
       *                           be writable
       *
       * @since 1.7
       */
      protected Error(String message, Throwable cause,
                      boolean enableSuppression,
                      boolean writableStackTrace) {
          super(message, cause, enableSuppression, writableStackTrace);
      }
  
      // DIFFBLUE MODEL LIBRARY
      // While Object.getClass() is not modelled, we can get the same
      // functionality by adding one toString() method per subclass of
      // Throwable.
      @Override
      public String toString() {
          String message = getLocalizedMessage();
          return (message != null)
              ? ("java.lang.Error: " + message)
              : "java.lang.Error";
      }
  }
  