diff --git a/gradle/wrapper/gradle-wrapper.jar b/gradle/wrapper/gradle-wrapper.jar
index c1962a79e..7f93135c4 100644
Binary files a/gradle/wrapper/gradle-wrapper.jar and b/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index 0c85a1f75..ac72c34e8 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,6 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.3-bin.zip
 networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/gradlew b/gradlew
index aeb74cbb4..0adc8e1a5 100755
--- a/gradlew
+++ b/gradlew
@@ -83,7 +83,8 @@ done
 # This is normally unused
 # shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
@@ -130,10 +131,13 @@ location of your Java installation."
     fi
 else
     JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+    if ! command -v java >/dev/null 2>&1
+    then
+        die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
+    fi
 fi
 
 # Increase the maximum file descriptors if we can.
diff --git a/platform/build.gradle.kts b/platform/build.gradle.kts
index 0a094609a..d0048155c 100644
--- a/platform/build.gradle.kts
+++ b/platform/build.gradle.kts
@@ -6,7 +6,7 @@ javaPlatform {
     allowDependencies()
 }
 
-val kotlinVersion = "1.8.10"
+val kotlinVersion = "1.9.10"
 val exposedVersion = "0.37.3"
 val lsp4jVersion = "0.15.0"
 
diff --git a/server/src/main/kotlin/org/javacs/kt/compiler/Compiler.kt b/server/src/main/kotlin/org/javacs/kt/compiler/Compiler.kt
index 13c201f50..1cfc25222 100644
--- a/server/src/main/kotlin/org/javacs/kt/compiler/Compiler.kt
+++ b/server/src/main/kotlin/org/javacs/kt/compiler/Compiler.kt
@@ -119,6 +119,11 @@ private class CompilationEnvironment(
                 // configure jvm runtime classpaths
                 configureJdkClasspathRoots()
 
+                // Kotlin 1.8.20 requires us to specify the JDK home, otherwise java.* classes won't resolve
+                // See https://github.com/JetBrains/kotlin-compiler-server/pull/626
+                val jdkHome = File(System.getProperty("java.home"))
+                put(JVMConfigurationKeys.JDK_HOME, jdkHome)
+
                 addJvmClasspathRoots(classPath.map { it.toFile() })
                 addJavaSourceRoots(javaSourcePath.map { it.toFile() })
 
diff --git a/server/src/test/resources/additionalWorkspace/gradle.properties b/server/src/test/resources/additionalWorkspace/gradle.properties
index 75966ef05..f1ec025b9 100644
--- a/server/src/test/resources/additionalWorkspace/gradle.properties
+++ b/server/src/test/resources/additionalWorkspace/gradle.properties
@@ -1 +1 @@
-kotlinVersion=1.8.10
+kotlinVersion=1.9.10
diff --git a/server/src/test/resources/additionalWorkspace/gradle/wrapper/gradle-wrapper.jar b/server/src/test/resources/additionalWorkspace/gradle/wrapper/gradle-wrapper.jar
index c1962a79e..7f93135c4 100644
Binary files a/server/src/test/resources/additionalWorkspace/gradle/wrapper/gradle-wrapper.jar and b/server/src/test/resources/additionalWorkspace/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/server/src/test/resources/additionalWorkspace/gradle/wrapper/gradle-wrapper.properties b/server/src/test/resources/additionalWorkspace/gradle/wrapper/gradle-wrapper.properties
index 0c85a1f75..ac72c34e8 100644
--- a/server/src/test/resources/additionalWorkspace/gradle/wrapper/gradle-wrapper.properties
+++ b/server/src/test/resources/additionalWorkspace/gradle/wrapper/gradle-wrapper.properties
@@ -1,6 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.3-bin.zip
 networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/server/src/test/resources/additionalWorkspace/gradlew b/server/src/test/resources/additionalWorkspace/gradlew
index aeb74cbb4..0adc8e1a5 100755
--- a/server/src/test/resources/additionalWorkspace/gradlew
+++ b/server/src/test/resources/additionalWorkspace/gradlew
@@ -83,7 +83,8 @@ done
 # This is normally unused
 # shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
@@ -130,10 +131,13 @@ location of your Java installation."
     fi
 else
     JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+    if ! command -v java >/dev/null 2>&1
+    then
+        die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
+    fi
 fi
 
 # Increase the maximum file descriptors if we can.