异常应用场景

Throwable

NoSuchElementException 的异常类典型写法，自定义异常类参考!

public
class NoSuchElementException extends RuntimeException {
    private static final long serialVersionUID = 6769829250639411880L;

    /**
     * Constructs a <code>NoSuchElementException</code> with <tt>null</tt>
     * as its error message string.
     */
    public NoSuchElementException() {
        super();
    }

    /**
     * Constructs a <code>NoSuchElementException</code>, saving a reference
     * to the error message string <tt>s</tt> for later retrieval by the
     * <tt>getMessage</tt> method.
     *
     * @param   s   the detail message.
     */
    public NoSuchElementException(String s) {
        super(s);
    }
}

Throwable cause 异常类构建

public class ConcurrentModificationException extends RuntimeException {
    private static final long serialVersionUID = -3666751008965953603L;

    /**
     * Constructs a ConcurrentModificationException with no
     * detail message.
     */
    public ConcurrentModificationException() {
    }

    /**
     * Constructs a {@code ConcurrentModificationException} with the
     * specified detail message.
     *
     * @param message the detail message pertaining to this exception.
     */
    public ConcurrentModificationException(String message) {
        super(message);
    }

    /**
     * Constructs a new exception 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}.
     *
     * @param  cause the cause (which is saved for later retrieval by the
     *         {@link Throwable#getCause()} method).  (A {@code null} value is
     *         permitted, and indicates that the cause is nonexistent or
     *         unknown.)
     * @since  1.7
     */
    public ConcurrentModificationException(Throwable cause) {
        super(cause);
    }

    /**
     * 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 Throwable#getMessage()} method).
     * @param  cause the cause (which is saved for later retrieval by the
     *         {@link Throwable#getCause()} method).  (A {@code null} value
     *         is permitted, and indicates that the cause is nonexistent or
     *         unknown.)
     * @since 1.7
     */
    public ConcurrentModificationException(String message, Throwable cause) {
        super(message, cause);
    }
}