GF/src is now for 2.9, and the new sources are in src-3.0 - keep it this way until the release of GF 3

src-3.0/JavaGUI/Utils.java

@@ -0,0 +1,22 @@
+
+import java.io.File;
+
+public class Utils {
+
+    public final static String gf = "gf";
+    public final static String gfcm = "gfcm";
+
+    /*
+     * Get the extension of a file.
+     */
+    public static String getExtension(File f) {
+        String ext = null;
+        String s = f.getName();
+        int i = s.lastIndexOf('.');
+
+        if (i > 0 &&  i < s.length() - 1) {
+            ext = s.substring(i+1).toLowerCase();
+        }
+        return ext;
+    }
+}