Add logging for java build

.github/workflows/release.yml

@@ -264,7 +264,15 @@ jobs:
               exit 1
             fi
           done
-          echo "Committed jar carries all three platform natives."
+          if ! unzip -Z1 "$jar" | grep -q '\.class$'; then
+            echo "::error::committed jar contains no compiled .class output; the JVM build did not compile"
+            exit 1
+          fi
+          if ! unzip -Z1 "$jar" | grep -q '\.kt$'; then
+            echo "::error::committed jar contains no .kt sources; the source bundling step did not run"
+            exit 1
+          fi
+          echo "Committed jar carries all three platform natives plus compiled classes and sources."
 
       - name: Configure AWS credentials
         uses: aws-actions/configure-aws-credentials@v6.2.0

src/bindings-jvm/build.sh

@@ -114,14 +114,28 @@ EOF
 echo "Compiling and packaging JAR via Gradle..."
 gradle --no-daemon --console=plain jar
 
+# ── Verify the JAR carries compiled classes and sources ──────────────────────
+# A jar that bundles the .kt sources but not the compiled .class output (e.g. a
+# Gradle source-set regression that drops the compilation output) still packages,
+# uploads, and publishes successfully, then fails every consumer at class-load time.
+# Assert both are present so that failure surfaces here rather than downstream.
+# There are no .java entries by design — the bindings are Kotlin-only.
+CLASS_COUNT=$(jar tf "$JAR_FILE" | grep -c '\.class$' || true)
+KT_COUNT=$(jar tf "$JAR_FILE" | grep -c '\.kt$' || true)
+if [ "$CLASS_COUNT" -eq 0 ] || [ "$KT_COUNT" -eq 0 ]; then
+    echo "Error: $JAR_FILE is missing compiled output — $CLASS_COUNT .class and $KT_COUNT .kt entries (both must be non-zero)." >&2
+    exit 1
+fi
+
 # ── Summary ───────────────────────────────────────────────────────────────────
 KT_SIZE=$(find "$GENERATED_DIR" -name '*.kt' -type f -exec cat {} + | wc -c | awk '{printf "%.1fM", $1/1048576}')
 LIB_SIZE=$(du -sh "$RELEASE_DIR/$LIB_NAME" | cut -f1)
 JAR_SIZE=$(du -sh "$JAR_FILE" | cut -f1)
 
 echo ""
 echo "Build complete: $GENERATED_DIR"
-echo "  Kotlin sources: $KT_SIZE"
+echo "  Kotlin sources: $KT_SIZE ($KT_COUNT .kt files bundled)"
+echo "  Compiled classes: $CLASS_COUNT .class entries bundled"
 echo "  Native library: $LIB_SIZE ($LIB_NAME, bundled in jar)"
 echo "  JAR:            $JAR_SIZE ($(basename "$JAR_FILE"))"
 echo ""

src/bindings-jvm/merge-jars.sh

@@ -15,6 +15,14 @@ OUT_JAR="$OUT_DIR/$(basename "$OUT_JAR")"
 
 BASE_JAR="$1"; shift
 echo "Base jar (classes + sources + native): $BASE_JAR"
+
+base_classes="$(unzip -Z1 "$BASE_JAR" | grep -c '\.class$' || true)"
+base_sources="$(unzip -Z1 "$BASE_JAR" | grep -c '\.kt$' || true)"
+if [ "$base_classes" -eq 0 ] || [ "$base_sources" -eq 0 ]; then
+    echo "Error: base jar $BASE_JAR is missing compiled output — $base_classes .class and $base_sources .kt entries (both must be non-zero)." >&2
+    exit 1
+fi
+
 cp "$BASE_JAR" "$OUT_JAR"
 
 for jar_file in "$@"; do