1 /*
2 * Copyright 1995-2004 Sun Microsystems, Inc. All Rights Reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Sun designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Sun in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
22 * CA 95054 USA or visit www.sun.com if you need additional information or
23 * have any questions.
24 */
25
26 package java.lang;
27
28 /**
29 * Thrown when an application tries to load in a class through its
30 * string name using:
31 * <ul>
32 * <li>The <code>forName</code> method in class <code>Class</code>.
33 * <li>The <code>findSystemClass</code> method in class
34 * <code>ClassLoader</code> .
35 * <li>The <code>loadClass</code> method in class <code>ClassLoader</code>.
36 * </ul>
37 * <p>
38 * but no definition for the class with the specified name could be found.
39 *
40 * <p>As of release 1.4, this exception has been retrofitted to conform to
41 * the general purpose exception-chaining mechanism. The "optional exception
42 * that was raised while loading the class" that may be provided at
43 * construction time and accessed via the {@link #getException()} method is
44 * now known as the <i>cause</i>, and may be accessed via the {@link
45 * Throwable#getCause()} method, as well as the aforementioned "legacy method."
46 *
47 * @author unascribed
48 * @see java.lang.Class#forName(java.lang.String)
49 * @see java.lang.ClassLoader#findSystemClass(java.lang.String)
50 * @see java.lang.ClassLoader#loadClass(java.lang.String, boolean)
51 * @since JDK1.0
52 */
53 public class ClassNotFoundException extends ReflectiveOperationException {
54 /**
55 * use serialVersionUID from JDK 1.1.X for interoperability
56 */
57 private static final long serialVersionUID = 9176873029745254542L;
58
59 /**
60 * This field holds the exception ex if the
61 * ClassNotFoundException(String s, Throwable ex) constructor was
62 * used to instantiate the object
63 * @serial
64 * @since 1.2
65 */
66 private Throwable ex;
67
68 /**
69 * Constructs a <code>ClassNotFoundException</code> with no detail message.
70 */
71 public ClassNotFoundException() {
72 super((Throwable)null); // Disallow initCause
73 }
74
75 /**
76 * Constructs a <code>ClassNotFoundException</code> with the
77 * specified detail message.
78 *
79 * @param s the detail message.
80 */
81 public ClassNotFoundException(String s) {
82 super(s, null); // Disallow initCause
83 }
84
85 /**
86 * Constructs a <code>ClassNotFoundException</code> with the
87 * specified detail message and optional exception that was
88 * raised while loading the class.
89 *
90 * @param s the detail message
91 * @param ex the exception that was raised while loading the class
92 * @since 1.2
93 */
94 public ClassNotFoundException(String s, Throwable ex) {
95 super(s, null); // Disallow initCause
96 this.ex = ex;
97 }
98
99 /**
100 * Returns the exception that was raised if an error occurred while
101 * attempting to load the class. Otherwise, returns <tt>null</tt>.
102 *
103 * <p>This method predates the general-purpose exception chaining facility.
104 * The {@link Throwable#getCause()} method is now the preferred means of
105 * obtaining this information.
106 *
107 * @return the <code>Exception</code> that was raised while loading a class
108 * @since 1.2
109 */
110 public Throwable getException() {
111 return ex;
112 }
113
114 /**
115 * Returns the cause of this exception (the exception that was raised
116 * if an error occurred while attempting to load the class; otherwise
117 * <tt>null</tt>).
118 *
119 * @return the cause of this exception.
120 * @since 1.4
121 */
122 public Throwable getCause() {
123 return ex;
124 }
125 }