/*
 * Copyright (c) 1995, 2004, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package java.lang;

/**
 * Thrown when an application tries to load in a class through its
 * string name using:
 * <ul>
 * <li>The <code>forName</code> method in class <code>Class</code>.
 * <li>The <code>findSystemClass</code> method in class
 *     <code>ClassLoader</code> .
 * <li>The <code>loadClass</code> method in class <code>ClassLoader</code>.
 * </ul>
 * <p>
 * but no definition for the class with the specified name could be found.
 *
 * <p>As of release 1.4, this exception has been retrofitted to conform to
 * the general purpose exception-chaining mechanism.  The "optional exception
 * that was raised while loading the class" that may be provided at
 * construction time and accessed via the {@link #getException()} method is
 * now known as the <i>cause</i>, and may be accessed via the {@link
 * Throwable#getCause()} method, as well as the aforementioned "legacy method."
 *
 * @author  unascribed
 * @see     java.lang.Class#forName(java.lang.String)
 * @see     java.lang.ClassLoader#findSystemClass(java.lang.String)
 * @see     java.lang.ClassLoader#loadClass(java.lang.String, boolean)
 * @since   JDK1.0
 */
public class ClassNotFoundException extends ReflectiveOperationException {
	/**
	 * use serialVersionUID from JDK 1.1.X for interoperability
	 */
	private static final long serialVersionUID = 9176873029745254542L;

	/**
	 * This field holds the exception ex if the
	 * ClassNotFoundException(String s, Throwable ex) constructor was
	 * used to instantiate the object
	 * @serial
	 * @since 1.2
	 */
	private Throwable ex;

	/**
	 * Constructs a <code>ClassNotFoundException</code> with no detail message.
	 */
	public ClassNotFoundException() {
		super((Throwable)null);  // Disallow initCause
	}

	/**
	 * Constructs a <code>ClassNotFoundException</code> with the
	 * specified detail message.
	 *
	 * @param   s   the detail message.
	 */
	public ClassNotFoundException(String s) {
		super(s, null);  //  Disallow initCause
	}

	/**
	 * Constructs a <code>ClassNotFoundException</code> with the
	 * specified detail message and optional exception that was
	 * raised while loading the class.
	 *
	 * @param s the detail message
	 * @param ex the exception that was raised while loading the class
	 * @since 1.2
	 */
	public ClassNotFoundException(String s, Throwable ex) {
		super(s, null);  //  Disallow initCause
		this.ex = ex;
	}

	/**
	 * Returns the exception that was raised if an error occurred while
	 * attempting to load the class. Otherwise, returns <tt>null</tt>.
	 *
	 * <p>This method predates the general-purpose exception chaining facility.
	 * The {@link Throwable#getCause()} method is now the preferred means of
	 * obtaining this information.
	 *
	 * @return the <code>Exception</code> that was raised while loading a class
	 * @since 1.2
	 */
	public Throwable getException() {
		return ex;
	}

	/**
	 * Returns the cause of this exception (the exception that was raised
	 * if an error occurred while attempting to load the class; otherwise
	 * <tt>null</tt>).
	 *
	 * @return  the cause of this exception.
	 * @since   1.4
	 */
	public Throwable getCause() {
		return ex;
	}
}
