Fix crash when unexisting subdir

src/serverP2P/ServerP2P.java

@@ -13,6 +13,7 @@ public class ServerP2P {
 
 	public ServerP2P() {
 		directories = new Directories("P2P_JAVA_PROJECT_SERVER");
+		directories.createSubdir(subdir);
 		logger = new Logger(directories.getDataHomeDirectory() + "server.log");
 		port = 40001;
 		System.out.println("Server will listen on port " + port + " and serve files from " + directories.getDataHomeDirectory() + subdir);

src/tools/Directories.java

@@ -48,6 +48,20 @@ public class Directories {
 		new File(dataHomeDirectory).mkdirs();
 	}
 
+	/** Create a subdirectory.
+	 * @param subdir	Name of subdirectory to create
+	 */
+	public void createSubdir(String subdir) {
+		String d = dataHomeDirectory;
+		if (subdir != null) {
+			d += subdir;
+			if (!subdir.endsWith("/")) {
+				d += "/";
+			}
+		}
+		new File(d).mkdirs();
+	}
+
 	/** Getter for dataHomeDirectory.
 	 * @return	path to the application home directory
 	 */