diff --git a/src/api-impl/meson.build b/src/api-impl/meson.build
index a28c0610..b00f58f2 100644
--- a/src/api-impl/meson.build
+++ b/src/api-impl/meson.build
@@ -518,5 +518,6 @@ hax_jar = jar('hax', [
               java_args: [
               	'-bootclasspath', bootclasspath,
               	'-source', '1.8', '-target', '1.8',
+              	'-encoding', 'UTF-8',
               	'-h', join_paths(dir_base, 'src/api-impl-jni/generated_headers')
               ])