RuntimeException.java

/*
 * 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
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package java.lang;

/**
 * {@code RuntimeException} is the superclass of those
 * exceptions that can be thrown during the normal operation of the
 * Java Virtual Machine.
 *
 * <p>{@code RuntimeException} and its subclasses are <em>unchecked
 * exceptions</em>.  Unchecked exceptions do <em>not</em> need to be
 * declared in a method or constructor's {@code throws} clause if they
 * can be thrown by the execution of the method or constructor and
 * propagate outside the method or constructor boundary.
 *
 * @author Frank Yellin
 * @jls 11.2 Compile-Time Checking of Exceptions
 * @since 1.0
 */
/*
 * 运行时异常，又称检查异常，编译前就需要捕获或抛出
 *
 * 异常体系：
 *                           Throwable
 *                               |
 *                    +----------+-----------+
 *                    |                      |
 *                Exception                Error
 *                    |                      |
 *        +-----------+-----------+         ...
 *        |                       |
 * RuntimeException              ...
 *        |
 *       ...
 *
 * Throwable       : 所有异常的祖先类
 * RuntimeException: 运行时异常，或称非检查异常；这类异常意味着程序出现了难以恢复的错误，允许不进行捕获
 * Exception       : 除运行时异常之外的异常，或称检查异常；这类异常意味着程序出现错误时可能是允许被恢复的，需要在编译期就捕获，否则无法编译
 * Error           : 非常严重的异常，该类异常往往意味着JVM内部出现了问题
 */
public class RuntimeException extends Exception {
    
    static final long serialVersionUID = -7034897190745766939L;
    
    /**
     * Constructs a new runtime exception with {@code null} as its
     * detail message.  The cause is not initialized, and may subsequently be
     * initialized by a call to {@link #initCause}.
     */
    public RuntimeException() {
        super();
    }
    
    /**
     * Constructs a new runtime 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 RuntimeException(String message) {
        super(message);
    }
    
    /**
     * Constructs a new runtime exception 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 runtime 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 {@code null} value is
     *                permitted, and indicates that the cause is nonexistent or
     *                unknown.)
     *
     * @since 1.4
     */
    public RuntimeException(String message, Throwable cause) {
        super(message, cause);
    }
    
    /**
     * Constructs a new runtime 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}).  This constructor is useful for runtime exceptions
     * 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 RuntimeException(Throwable cause) {
        super(cause);
    }
    
    /**
     * Constructs a new runtime exception 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 RuntimeException(String message, Throwable cause, boolean enableSuppression, boolean writableStackTrace) {
        super(message, cause, enableSuppression, writableStackTrace);
    }
}