--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/main/gov/nasa/jpf/JPFShell.java	Fri Jan 23 10:14:01 2015 -0800
@@ -0,0 +1,42 @@
+/*
+ * Copyright (C) 2014, United States Government, as represented by the
+ * Administrator of the National Aeronautics and Space Administration.
+ * All rights reserved.
+ *
+ * The Java Pathfinder core (jpf-core) platform is licensed under the
+ * Apache License, Version 2.0 (the "License"); you may not use this file except
+ * in compliance with the License. You may obtain a copy of the License at
+ * 
+ *        http://www.apache.org/licenses/LICENSE-2.0. 
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and 
+ * limitations under the License.
+ */
+
+package gov.nasa.jpf;
+
+/**
+ * type that can be used to instantiate and run a JPF object
+ * Shell objects can be configured via the JPF 'shell' property, and are
+ * typically JPF user interface implementations
+ * 
+ * Instantiation and start() call are done from the JPF.main() method
+ *
+ * Usually, JPFShell implementors have a <init>(Config) ctor so that they
+ * don't need to obtain a new Config object. This is the reason for
+ * using a shell *instance* instead of a static main() method - we cannot
+ * pass the Config object that was already created by JPF.main() at this point
+ * into the shell main(), which means we would either have to turn Config
+ * into a singleton (causing problems for multiple JPF runs), or create a new
+ * Config object within the shell. Since initialization of Config objects is
+ * an expensive task with our new bootstrapping, it seems better to pass the
+ * Config object from JPF.main() (which is done automatically when using
+ * Config based initialization)
+ */
+public interface JPFShell {
+
+  void start(String[] args);
+}