--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/src/jdk.jshell/share/classes/jdk/jshell/Diag.java	Mon Oct 19 19:15:16 2015 +0200
@@ -0,0 +1,130 @@
+/*
+ * Copyright (c) 2015, 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 jdk.jshell;
+
+import java.util.Locale;
+import javax.tools.Diagnostic;
+
+/**
+ * Diagnostic information for a Snippet.
+ * @see jdk.jshell.JShell#diagnostics(jdk.jshell.Snippet)
+ */
+public abstract class Diag {
+    // Simplified view on compiler Diagnostic.
+
+    /**
+     * Used to signal that no position is available.
+     */
+    public final static long NOPOS = Diagnostic.NOPOS;
+
+    /**
+     * Is this diagnostic and error (as opposed to a warning or note)
+     * @return true if this diagnostic is an error
+     */
+    public abstract boolean isError();
+
+    /**
+     * Returns a character offset from the beginning of the source object
+     * associated with this diagnostic that indicates the location of
+     * the problem.  In addition, the following must be true:
+     *
+     * <p>{@code getStartPostion() <= getPosition()}
+     * <p>{@code getPosition() <= getEndPosition()}
+     *
+     * @return character offset from beginning of source; {@link
+     * #NOPOS} if {@link #getSource()} would return {@code null} or if
+     * no location is suitable
+     */
+    public abstract long getPosition();
+
+    /**
+     * Returns the character offset from the beginning of the file
+     * associated with this diagnostic that indicates the start of the
+     * problem.
+     *
+     * @return offset from beginning of file; {@link #NOPOS} if and
+     * only if {@link #getPosition()} returns {@link #NOPOS}
+     */
+    public abstract long getStartPosition();
+
+    /**
+     * Returns the character offset from the beginning of the file
+     * associated with this diagnostic that indicates the end of the
+     * problem.
+     *
+     * @return offset from beginning of file; {@link #NOPOS} if and
+     * only if {@link #getPosition()} returns {@link #NOPOS}
+     */
+    public abstract long getEndPosition();
+
+    /**
+     * Returns a diagnostic code indicating the type of diagnostic.  The
+     * code is implementation-dependent and might be {@code null}.
+     *
+     * @return a diagnostic code
+     */
+    public abstract String getCode();
+
+    /**
+     * Returns a localized message for the given locale.  The actual
+     * message is implementation-dependent.  If the locale is {@code
+     * null} use the default locale.
+     *
+     * @param locale a locale; might be {@code null}
+     * @return a localized message
+     */
+    public abstract String getMessage(Locale locale);
+
+    // *** Internal support ***
+
+    /**
+     * Internal: If this is from a compile, extract the compilation Unit.
+     * Otherwise null.
+     */
+    abstract Unit unitOrNull();
+
+    /**
+     * This is an unreachable-statement error
+     */
+    boolean isUnreachableError() {
+        return getCode().equals("compiler.err.unreachable.stmt");
+    }
+
+    /**
+     * This is a not-a-statement error
+     */
+    boolean isNotAStatementError() {
+        return getCode().equals("compiler.err.not.stmt");
+    }
+
+    /**
+     * This is a resolution error.
+     */
+    boolean isResolutionError() {
+        //TODO: try javac RESOLVE_ERROR flag
+        return getCode().startsWith("compiler.err.cant.resolve");
+    }
+}