1/*
2 * Copyright (c) 1995, 2004, Oracle and/or its affiliates. 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.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26package 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   1.0
52 */
53public 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 {@code null}.
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     * {@code null}).
118     *
119     * @return  the cause of this exception.
120     * @since   1.4
121     */
122    public Throwable getCause() {
123        return ex;
124    }
125}
126