--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/java/util/concurrent/Callable.java	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,65 @@
+/*
+ * 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.  Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+/*
+ * This file is available under and governed by the GNU General Public
+ * License version 2 only, as published by the Free Software Foundation.
+ * However, the following notice accompanied the original version of this
+ * file:
+ *
+ * Written by Doug Lea with assistance from members of JCP JSR-166
+ * Expert Group and released to the public domain, as explained at
+ * http://creativecommons.org/licenses/publicdomain
+ */
+
+package java.util.concurrent;
+
+/**
+ * A task that returns a result and may throw an exception.
+ * Implementors define a single method with no arguments called
+ * <tt>call</tt>.
+ *
+ * <p>The <tt>Callable</tt> interface is similar to {@link
+ * java.lang.Runnable}, in that both are designed for classes whose
+ * instances are potentially executed by another thread.  A
+ * <tt>Runnable</tt>, however, does not return a result and cannot
+ * throw a checked exception.
+ *
+ * <p> The {@link Executors} class contains utility methods to
+ * convert from other common forms to <tt>Callable</tt> classes.
+ *
+ * @see Executor
+ * @since 1.5
+ * @author Doug Lea
+ * @param <V> the result type of method <tt>call</tt>
+ */
+public interface Callable<V> {
+    /**
+     * Computes a result, or throws an exception if unable to do so.
+     *
+     * @return computed result
+     * @throws Exception if unable to compute a result
+     */
+    V call() throws Exception;
+}