Compile Java during make, not during tests

Re-organised all Java source code under the java-api subdirectory, which
also contains a Makefile.in that performs the Java compilation.  This
makefile is only invoked if ./configure finds a working Java compiler.

java-api/src/org/servalproject/servaldna/meshms/MeshMSException.java

@@ -0,0 +1,40 @@
+/**
+ * Copyright (C) 2014 Serval Project Inc.
+ *
+ * This file is part of Serval Software (http://www.servalproject.org)
+ *
+ * Serval Software is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This source 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 for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this source code; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+package org.servalproject.servaldna.meshms;
+
+import java.net.URL;
+
+/**
+ * Thrown when a MeshMS API encounters an exceptional condition.  This exception is subclassed for
+ * specific causes.
+ *
+ * @author Andrew Bettison <andrew@servalproject.com>
+ */
+public abstract class MeshMSException extends Exception
+{
+	public final URL url;
+
+	public MeshMSException(String message, URL url) {
+		super(message + "; " + (url==null?"(null)":url));
+		this.url = url;
+	}
+
+}