diff --git a/examples/build.gradle.kts b/examples/build.gradle.kts
index 6afd9c21..f44b65da 100644
--- a/examples/build.gradle.kts
+++ b/examples/build.gradle.kts
@@ -17,7 +17,7 @@ plugins {
 }
 
 kotlin {
-    jvmToolchain(11)
+    jvmToolchain(8)
 }
 
 dependencies {
diff --git a/examples/src/main/java/io/zenoh/ZGet.java b/examples/src/main/java/io/zenoh/ZGet.java
index a8dbb262..53a3094a 100644
--- a/examples/src/main/java/io/zenoh/ZGet.java
+++ b/examples/src/main/java/io/zenoh/ZGet.java
@@ -32,7 +32,7 @@ public static void main(String[] args) throws ZenohException, InterruptedExcepti
                 assert receiver != null;
                 while (true) {
                     Optional<Reply> wrapper = receiver.take();
-                    if (wrapper.isEmpty()) {
+                    if (!wrapper.isPresent()) {
                         break;
                     }
                     Reply reply = wrapper.get();
diff --git a/examples/src/main/java/io/zenoh/ZQueryable.java b/examples/src/main/java/io/zenoh/ZQueryable.java
index c5a9c872..8ccef6b9 100644
--- a/examples/src/main/java/io/zenoh/ZQueryable.java
+++ b/examples/src/main/java/io/zenoh/ZQueryable.java
@@ -44,7 +44,7 @@ public static void main(String[] args) throws ZenohException, InterruptedExcepti
     private static void handleRequests(BlockingQueue<Optional<Query>> receiver, KeyExpr keyExpr) throws InterruptedException {
         while (true) {
             Optional<Query> wrapper = receiver.take();
-            if (wrapper.isEmpty()) {
+            if (!wrapper.isPresent()) {
                 break;
             }
             Query query = wrapper.get();
diff --git a/examples/src/main/java/io/zenoh/ZSub.java b/examples/src/main/java/io/zenoh/ZSub.java
index 883139f7..08171083 100644
--- a/examples/src/main/java/io/zenoh/ZSub.java
+++ b/examples/src/main/java/io/zenoh/ZSub.java
@@ -35,7 +35,7 @@ public static void main(String[] args) throws ZenohException, InterruptedExcepti
                     System.out.println("Press CTRL-C to quit...");
                     while (true) {
                         Optional<Sample> wrapper = receiver.take();
-                        if (wrapper.isEmpty()) {
+                        if (!wrapper.isPresent()) {
                             break;
                         }
                         Sample sample = wrapper.get();
diff --git a/zenoh-java/build.gradle.kts b/zenoh-java/build.gradle.kts
index f5841d0a..b1cc1e6e 100644
--- a/zenoh-java/build.gradle.kts
+++ b/zenoh-java/build.gradle.kts
@@ -37,10 +37,10 @@ if (androidEnabled) {
 }
 
 kotlin {
-    jvmToolchain(11)
+    jvmToolchain(8)
     jvm {
         compilations.all {
-            kotlinOptions.jvmTarget = "11"
+            kotlinOptions.jvmTarget = "1.8"
         }
         testRuns["test"].executionTask.configure {
             val zenohPaths = "../zenoh-jni/target/$buildMode"
@@ -167,17 +167,17 @@ enum class BuildMode {
 fun Project.configureAndroid() {
     extensions.configure<com.android.build.gradle.LibraryExtension>("android") {
         namespace = "io.zenoh"
-        compileSdk = 30
+        compileSdk = 27
 
         ndkVersion = "26.0.10792818"
 
         defaultConfig {
-            minSdk = 30
+            minSdk = 27
         }
 
         compileOptions {
-            sourceCompatibility = JavaVersion.VERSION_11
-            targetCompatibility = JavaVersion.VERSION_11
+            sourceCompatibility = JavaVersion.VERSION_1_8
+            targetCompatibility = JavaVersion.VERSION_1_8
         }
 
         buildTypes {