001/*
002 * Copyright 2002-2018 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      https://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.springframework.web.util;
018
019import javax.servlet.ServletException;
020
021import org.springframework.core.NestedExceptionUtils;
022import org.springframework.lang.Nullable;
023
024/**
025 * Subclass of {@link ServletException} that properly handles a root cause in terms
026 * of message and stacktrace, just like NestedChecked/RuntimeException does.
027 *
028 * <p>Note that the plain ServletException doesn't expose its root cause at all,
029 * neither in the exception message nor in printed stack traces! While this might
030 * be fixed in later Servlet API variants (which even differ per vendor for the
031 * same API version), it is not reliably available on Servlet 2.4 (the minimum
032 * version required by Spring 3.x), which is why we need to do it ourselves.
033 *
034 * <p>The similarity between this class and the NestedChecked/RuntimeException
035 * class is unavoidable, as this class needs to derive from ServletException.
036 *
037 * @author Juergen Hoeller
038 * @since 1.2.5
039 * @see #getMessage
040 * @see #printStackTrace
041 * @see org.springframework.core.NestedCheckedException
042 * @see org.springframework.core.NestedRuntimeException
043 */
044public class NestedServletException extends ServletException {
045
046        /** Use serialVersionUID from Spring 1.2 for interoperability. */
047        private static final long serialVersionUID = -5292377985529381145L;
048
049        static {
050                // Eagerly load the NestedExceptionUtils class to avoid classloader deadlock
051                // issues on OSGi when calling getMessage(). Reported by Don Brown; SPR-5607.
052                NestedExceptionUtils.class.getName();
053        }
054
055
056        /**
057         * Construct a {@code NestedServletException} with the specified detail message.
058         * @param msg the detail message
059         */
060        public NestedServletException(String msg) {
061                super(msg);
062        }
063
064        /**
065         * Construct a {@code NestedServletException} with the specified detail message
066         * and nested exception.
067         * @param msg the detail message
068         * @param cause the nested exception
069         */
070        public NestedServletException(@Nullable String msg, @Nullable Throwable cause) {
071                super(msg, cause);
072        }
073
074
075        /**
076         * Return the detail message, including the message from the nested exception
077         * if there is one.
078         */
079        @Override
080        @Nullable
081        public String getMessage() {
082                return NestedExceptionUtils.buildMessage(super.getMessage(), getCause());
083        }
084
085}