diff --git a/src/main/java/com/github/nkzawa/socketio/client/Url.java b/src/main/java/com/github/nkzawa/socketio/client/Url.java
index 292b337..4e0de0a 100644
--- a/src/main/java/com/github/nkzawa/socketio/client/Url.java
+++ b/src/main/java/com/github/nkzawa/socketio/client/Url.java
@@ -21,7 +21,7 @@ public class Url {
         }
 
         String path = uri.getPath();
-        if (path == null || path.isEmpty()) {
+        if (path == null || path.length() == 0) {
             uri = uri.resolve("/");
         }
 
diff --git a/src/main/java/com/github/nkzawa/socketio/parser/Parser.java b/src/main/java/com/github/nkzawa/socketio/parser/Parser.java
index 1305dc9..a6138b8 100644
--- a/src/main/java/com/github/nkzawa/socketio/parser/Parser.java
+++ b/src/main/java/com/github/nkzawa/socketio/parser/Parser.java
@@ -97,7 +97,7 @@ public class Parser {
                 str.append("-");
             }
 
-            if (obj.nsp != null && !obj.nsp.isEmpty() && !"/".equals(obj.nsp)) {
+            if (obj.nsp != null && obj.nsp.length() != 0 && !"/".equals(obj.nsp)) {
                 nsp = true;
                 str.append(obj.nsp);
             }