1 /*
   2  * Copyright (c) 1999, 2018, 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 
  26 package java.lang.reflect;
  27 
  28 import java.io.IOException;
  29 import java.io.ObjectInputStream;
  30 import java.io.ObjectOutputStream;
  31 import java.io.ObjectStreamField;
  32 import jdk.internal.access.SharedSecrets;
  33 
  34 /**
  35  * Thrown by a method invocation on a proxy instance if its invocation
  36  * handler's {@link InvocationHandler#invoke invoke} method throws a
  37  * checked exception (a {@code Throwable} that is not assignable
  38  * to {@code RuntimeException} or {@code Error}) that
  39  * is not assignable to any of the exception types declared in the
  40  * {@code throws} clause of the method that was invoked on the
  41  * proxy instance and dispatched to the invocation handler.
  42  *
  43  * <p>An {@code UndeclaredThrowableException} instance contains
  44  * the undeclared checked exception that was thrown by the invocation
  45  * handler, and it can be retrieved with the
  46  * {@code getUndeclaredThrowable()} method.
  47  * {@code UndeclaredThrowableException} extends
  48  * {@code RuntimeException}, so it is an unchecked exception
  49  * that wraps a checked exception.
  50  *
  51  * <p>As of release 1.4, this exception has been retrofitted to
  52  * conform to the general purpose exception-chaining mechanism.  The
  53  * "undeclared checked exception that was thrown by the invocation
  54  * handler" that may be provided at construction time and accessed via
  55  * the {@link #getUndeclaredThrowable()} method is now known as the
  56  * <i>cause</i>, and may be accessed via the {@link
  57  * Throwable#getCause()} method, as well as the aforementioned "legacy
  58  * method."
  59  *
  60  * @author      Peter Jones
  61  * @see         InvocationHandler
  62  * @since       1.3
  63  */
  64 public class UndeclaredThrowableException extends RuntimeException {
  65     @java.io.Serial
  66     static final long serialVersionUID = 330127114055056639L;
  67 
  68     /**
  69      * Constructs an {@code UndeclaredThrowableException} with the
  70      * specified {@code Throwable}.
  71      *
  72      * @param   undeclaredThrowable the undeclared checked exception
  73      *          that was thrown
  74      */
  75     public UndeclaredThrowableException(Throwable undeclaredThrowable) {
  76         super(null, undeclaredThrowable);  // Disallow initCause
  77     }
  78 
  79     /**
  80      * Constructs an {@code UndeclaredThrowableException} with the
  81      * specified {@code Throwable} and a detail message.
  82      *
  83      * @param   undeclaredThrowable the undeclared checked exception
  84      *          that was thrown
  85      * @param   s the detail message
  86      */
  87     public UndeclaredThrowableException(Throwable undeclaredThrowable,
  88                                         String s)
  89     {
  90         super(s, undeclaredThrowable);  // Disallow initCause
  91     }
  92 
  93     /**
  94      * Returns the {@code Throwable} instance wrapped in this
  95      * {@code UndeclaredThrowableException}, which may be {@code null}.
  96      *
  97      * <p>This method predates the general-purpose exception chaining facility.
  98      * The {@link Throwable#getCause()} method is now the preferred means of
  99      * obtaining this information.
 100      *
 101      * @return the undeclared checked exception that was thrown
 102      */
 103     public Throwable getUndeclaredThrowable() {
 104         return super.getCause();
 105     }
 106 
 107     /**
 108      * Serializable fields for UndeclaredThrowableException.
 109      *
 110      * @serialField undeclaredThrowable Throwable
 111      */
 112     @java.io.Serial
 113     private static final ObjectStreamField[] serialPersistentFields = {
 114         new ObjectStreamField("undeclaredThrowable", Throwable.class)
 115     };
 116 
 117     /*
 118      * Reconstitutes the UndeclaredThrowableException instance from a stream
 119      * and initialize the cause properly when deserializing from an older
 120      * version.
 121      */
 122     @java.io.Serial
 123     private void readObject(ObjectInputStream s) throws IOException, ClassNotFoundException {
 124         ObjectInputStream.GetField fields = s.readFields();
 125         Throwable exception = (Throwable) fields.get("undeclaredThrowable", null);
 126         if (exception != null) {
 127             SharedSecrets.getJavaLangAccess().setCause(this, exception);
 128         }
 129     }
 130 
 131     /*
 132      * To maintain compatibility with older implementation, write a serial
 133      * "ex" field with the cause as the value.
 134      */
 135     @java.io.Serial
 136     private void writeObject(ObjectOutputStream out) throws IOException {
 137         ObjectOutputStream.PutField fields = out.putFields();
 138         fields.put("undeclaredThrowable", super.getCause());
 139         out.writeFields();
 140     }
 141 }