diff --git a/Rakefile b/Rakefile
index 6e79e08b7f..80b00bd913 100644
--- a/Rakefile
+++ b/Rakefile
@@ -45,8 +45,7 @@ elsif RUBY_ENGINE == "jruby"
     ext.name = "prism"
     ext.ext_dir = "java"
     ext.lib_dir = "tmp"
-    ext.source_version = "1.8"
-    ext.target_version = "1.8"
+    ext.release = "21"
     ext.gem_spec = Gem::Specification.load("prism.gemspec")
   end
 end
diff --git a/templates/java/org/ruby_lang/prism/Loader.java.erb b/templates/java/org/ruby_lang/prism/Loader.java.erb
index b48dd4c1cb..3c2a0cfd09 100644
--- a/templates/java/org/ruby_lang/prism/Loader.java.erb
+++ b/templates/java/org/ruby_lang/prism/Loader.java.erb
@@ -59,10 +59,7 @@ public class Loader {
                 int length = buffer.getInt(offset + 4);
 
                 byte[] bytes = new byte[length];
-                int position = buffer.position();
-                buffer.position(start);
-                buffer.get(bytes, 0, length);
-                buffer.position(position);
+                buffer.get(start, bytes);
 
                 constant = loader.bytesToName(bytes);
                 cache[index] = constant;