Android: Java 17 для Gradle (7.6.4 не тянет Java 21)

provision ставит openjdk-17, build-android.sh задаёт JAVA_HOME на
java-17 перед flutter build apk (как RustDesk CI).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

scripts/build-android.sh

@@ -78,7 +78,10 @@ cp ./target/aarch64-linux-android/release/liblibrustdesk.so "$JNI/librustdesk.so
 cp "$ANDROID_NDK_HOME/toolchains/llvm/prebuilt/linux-x86_64/sysroot/usr/lib/aarch64-linux-android/libc++_shared.so" "$JNI/"
 
 # --- APK ---
-echo "[apk] flutter build apk --release --target-platform android-arm64 --split-per-abi ..."
+# Gradle 7.6.4 не совместим с Java 21 (дефолт VM) -> используем Java 17 (как RustDesk CI).
+export JAVA_HOME=/usr/lib/jvm/java-17-openjdk-amd64
+export PATH="$JAVA_HOME/bin:$PATH"
+echo "[apk] flutter build apk (JAVA_HOME=$JAVA_HOME) ..."
 ( cd flutter && flutter build apk --release --target-platform android-arm64 --split-per-abi )
 
 # --- вынести артефакт ---

scripts/provision-android.sh

@@ -19,7 +19,8 @@ echo "[apt] deps..."
 sudo apt-get update -qq
 sudo DEBIAN_FRONTEND=noninteractive apt-get install -y -qq \
   clang libclang-dev cmake ninja-build nasm yasm pkg-config build-essential \
-  libssl-dev curl git unzip xz-utils zip python3-pip >/dev/null   # libssl-dev: host openssl-sys
+  libssl-dev openjdk-17-jdk-headless curl git unzip xz-utils zip python3-pip >/dev/null
+  # libssl-dev: host openssl-sys; openjdk-17: Gradle 7.6.4 не совместим с Java 21
 
 # --- Rust + aarch64-android ---
 if [ ! -x "$HOME/.cargo/bin/rustc" ] && ! command -v rustc >/dev/null; then