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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