std::exception vs java.lang.Exception

/*
 * %W% %E%
 *
 * Copyright (c) 2006, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package java.lang;

/**
 * The class <code>Exception</code> and its subclasses are a form of 
 * <code>Throwable</code> that indicates conditions that a reasonable 
 * application might want to catch.
 *
 * @author  Frank Yellin
 * @version %I%, %G%
 * @see     java.lang.Error
 * @since   JDK1.0
 */
public class Exception extends Throwable {
    static final long serialVersionUID = -3387516993124229948L;

    /**
     * Constructs a new exception with <code>null</code> as its detail message.
     * The cause is not initialized, and may subsequently be initialized by a
     * call to {@link #initCause}.
     */
    public Exception() {
    super();
    }

    /**
     * Constructs a new exception 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 Exception(String message) {
    super(message);
    }

    /**
     * Constructs a new exception with the specified detail message and
     * cause.  <p>Note that the detail message associated with
     * <code>cause</code> is <i>not</i> automatically incorporated in
     * this exception'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 <tt>null</tt> value is
     *         permitted, and indicates that the cause is nonexistent or
     *         unknown.)
     * @since  1.4
     */
    public Exception(String message, Throwable cause) {
        super(message, cause);
    }

    /**
     * Constructs a new exception with the specified cause and a detail
     * message of <tt>(cause==null ? null : cause.toString())</tt> (which
     * typically contains the class and detail message of <tt>cause</tt>).
     * This constructor is useful for exceptions that are little more than
     * wrappers for other throwables (for example, {@link
     * java.security.PrivilegedActionException}).
     *
     * @param  cause the cause (which is saved for later retrieval by the
     *         {@link #getCause()} method).  (A <tt>null</tt> value is
     *         permitted, and indicates that the cause is nonexistent or
     *         unknown.)
     * @since  1.4
     */
    public Exception(Throwable cause) {
        super(cause);
    }
}

  /**
   *  @brief Base class for all library exceptions.
   *
   *  This is the base class for all exceptions thrown by the standard
   *  library, and by certain language expressions.  You are free to derive
   *  your own %exception classes, or use a different hierarchy, or to
   *  throw non-class data (e.g., fundamental types).
   */
  class exception
  {
  public:
    exception() _GLIBCXX_USE_NOEXCEPT { }
    virtual ~exception() _GLIBCXX_USE_NOEXCEPT;

    /** Returns a C-style character string describing the general cause
     *  of the current error.  */
    virtual const char* what() const _GLIBCXX_USE_NOEXCEPT;
  };

class exception
{
public:

    exception() throw()
        : _Data()
    {
    }

    explicit exception(char const* const _Message) throw()
        : _Data()
    {
        __std_exception_data _InitData = { _Message, true };
        __std_exception_copy(&_InitData, &_Data);
    }

    exception(char const* const _Message, int) throw()
        : _Data()
    {
        _Data._What = _Message;
    }

    exception(exception const& _Other) throw()
        : _Data()
    {
        __std_exception_copy(&_Other._Data, &_Data);
    }

    exception& operator=(exception const& _Other) throw()
    {
        if (this == &_Other)
        {
            return *this;
        }

        __std_exception_destroy(&_Data);
        __std_exception_copy(&_Other._Data, &_Data);
        return *this;
    }

    virtual ~exception() throw()
    {
        __std_exception_destroy(&_Data);
    }

    virtual char const* what() const
    {
        return _Data._What ? _Data._What : "Unknown exception";
    }

private:

    __std_exception_data _Data;
};