diff --git a/src/main/java/com/meilisearch/sdk/Client.java b/src/main/java/com/meilisearch/sdk/Client.java
index 37e250eb..2613dc52 100644
--- a/src/main/java/com/meilisearch/sdk/Client.java
+++ b/src/main/java/com/meilisearch/sdk/Client.java
@@ -258,7 +258,7 @@ public String health() throws MeilisearchException {
      * @see <a href="https://www.meilisearch.com/docs/reference/api/health#health">API
      *     specification</a>
      */
-    public Boolean isHealthy() throws MeilisearchException {
+    public boolean isHealthy() throws MeilisearchException {
         return this.instanceHandler.isHealthy();
     }
 
@@ -510,7 +510,7 @@ public String generateTenantToken(
         Date now = new Date();
         String secret;
 
-        if (options.getApiKey() == null || options.getApiKey() == "") {
+        if (options.getApiKey() == null || options.getApiKey().isEmpty()) {
             secret = this.config.apiKey;
         } else {
             secret = options.getApiKey();
@@ -519,7 +519,7 @@ public String generateTenantToken(
         if (options.getExpiresAt() != null && now.after((Date) options.getExpiresAt())) {
             throw new MeilisearchException("The date expiresAt should be in the future.");
         }
-        if (secret == null || secret == "" || secret.length() <= 8) {
+        if (secret == null || secret.length() <= 8) {
             throw new MeilisearchException(
                     "An api key is required in the client or should be passed as an argument and this key cannot be the master key.");
         }
@@ -527,7 +527,7 @@ public String generateTenantToken(
             throw new MeilisearchException(
                     "The searchRules field is mandatory and should be defined.");
         }
-        if (apiKeyUid == "" || apiKeyUid == null || !isValidUUID(apiKeyUid)) {
+        if (apiKeyUid == null || apiKeyUid.isEmpty() || !isValidUUID(apiKeyUid)) {
             throw new MeilisearchException(
                     "The uid used for the token generation must exist and comply to uuid4 format");
         }
@@ -604,7 +604,7 @@ public void deleteWebhook(UUID webhookUuid) throws MeilisearchException {
         this.webHooksHandler.deleteWebhook(webhookUuid);
     }
 
-    private Boolean isValidUUID(String apiKeyUid) {
+    private boolean isValidUUID(String apiKeyUid) {
         try {
             UUID uuid = UUID.fromString(apiKeyUid);
         } catch (IllegalArgumentException exception) {