001 /*
002 * Copyright 1995-2004 Sun Microsystems, Inc. All Rights Reserved.
003 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
004 *
005 * This code is free software; you can redistribute it and/or modify it
006 * under the terms of the GNU General Public License version 2 only, as
007 * published by the Free Software Foundation. Sun designates this
008 * particular file as subject to the "Classpath" exception as provided
009 * by Sun in the LICENSE file that accompanied this code.
010 *
011 * This code is distributed in the hope that it will be useful, but WITHOUT
012 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
013 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
014 * version 2 for more details (a copy is included in the LICENSE file that
015 * accompanied this code).
016 *
017 * You should have received a copy of the GNU General Public License version
018 * 2 along with this work; if not, write to the Free Software Foundation,
019 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
020 *
021 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
022 * CA 95054 USA or visit www.sun.com if you need additional information or
023 * have any questions.
024 */
025
026 package java.lang;
027
028 /**
029 * Thrown when an application tries to load in a class through its
030 * string name using:
031 * <ul>
032 * <li>The <code>forName</code> method in class <code>Class</code>.
033 * <li>The <code>findSystemClass</code> method in class
034 * <code>ClassLoader</code> .
035 * <li>The <code>loadClass</code> method in class <code>ClassLoader</code>.
036 * </ul>
037 * <p>
038 * but no definition for the class with the specified name could be found.
039 *
040 * <p>As of release 1.4, this exception has been retrofitted to conform to
041 * the general purpose exception-chaining mechanism. The "optional exception
042 * that was raised while loading the class" that may be provided at
043 * construction time and accessed via the {@link #getException()} method is
044 * now known as the <i>cause</i>, and may be accessed via the {@link
045 * Throwable#getCause()} method, as well as the aforementioned "legacy method."
046 *
047 * @author unascribed
048 * @version 1.27, 05/05/07
049 * @see java.lang.Class#forName(java.lang.String)
050 * @see java.lang.ClassLoader#findSystemClass(java.lang.String)
051 * @see java.lang.ClassLoader#loadClass(java.lang.String, boolean)
052 * @since JDK1.0
053 */
054 public class ClassNotFoundException extends Exception {
055 /**
056 * use serialVersionUID from JDK 1.1.X for interoperability
057 */
058 private static final long serialVersionUID = 9176873029745254542L;
059
060 /**
061 * This field holds the exception ex if the
062 * ClassNotFoundException(String s, Throwable ex) constructor was
063 * used to instantiate the object
064 * @serial
065 * @since 1.2
066 */
067 private Throwable ex;
068
069 /**
070 * Constructs a <code>ClassNotFoundException</code> with no detail message.
071 */
072 public ClassNotFoundException() {
073 super ((Throwable) null); // Disallow initCause
074 }
075
076 /**
077 * Constructs a <code>ClassNotFoundException</code> with the
078 * specified detail message.
079 *
080 * @param s the detail message.
081 */
082 public ClassNotFoundException(String s) {
083 super (s, null); // Disallow initCause
084 }
085
086 /**
087 * Constructs a <code>ClassNotFoundException</code> with the
088 * specified detail message and optional exception that was
089 * raised while loading the class.
090 *
091 * @param s the detail message
092 * @param ex the exception that was raised while loading the class
093 * @since 1.2
094 */
095 public ClassNotFoundException(String s, Throwable ex) {
096 super (s, null); // Disallow initCause
097 this .ex = ex;
098 }
099
100 /**
101 * Returns the exception that was raised if an error occurred while
102 * attempting to load the class. Otherwise, returns <tt>null</tt>.
103 *
104 * <p>This method predates the general-purpose exception chaining facility.
105 * The {@link Throwable#getCause()} method is now the preferred means of
106 * obtaining this information.
107 *
108 * @return the <code>Exception</code> that was raised while loading a class
109 * @since 1.2
110 */
111 public Throwable getException() {
112 return ex;
113 }
114
115 /**
116 * Returns the cause of this exception (the exception that was raised
117 * if an error occurred while attempting to load the class; otherwise
118 * <tt>null</tt>).
119 *
120 * @return the cause of this exception.
121 * @since 1.4
122 */
123 public Throwable getCause() {
124 return ex;
125 }
126 }
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