diff --git a/core/src/main/java/org/jruby/api/MRI.java b/core/src/main/java/org/jruby/api/MRI.java
index d1d2c93600c..298ec484494 100644
--- a/core/src/main/java/org/jruby/api/MRI.java
+++ b/core/src/main/java/org/jruby/api/MRI.java
@@ -11,6 +11,7 @@
 import org.jruby.runtime.ThreadContext;
 import org.jruby.runtime.builtin.IRubyObject;
 import org.jruby.util.ByteList;
+import org.jruby.util.ByteListHolder;
 import org.jruby.util.io.EncodingUtils;
 import org.jruby.util.io.IOEncodable;
 import org.jruby.util.io.OpenFile;
@@ -173,6 +174,18 @@ public static Encoding rb_default_external_encoding(ThreadContext context) {
         return EncodingUtils.defaultExternalEncoding(context.runtime);
     }
 
+    public static void  rb_str_buf_cat(Ruby runtime, RubyString str, ByteList ptr) {
+        EncodingUtils.rbStrBufCat(runtime, str, ptr);
+    }
+
+    public static void  rb_str_buf_cat(Ruby runtime, ByteListHolder str, byte[] ptrBytes, int ptr, int len) {
+        EncodingUtils.rbStrBufCat(runtime, str, ptrBytes, ptr, len);
+    }
+
+    public static void  rb_str_buf_cat(Ruby runtime, ByteList str, byte[] ptrBytes, int ptr, int len) {
+        EncodingUtils.rbStrBufCat(runtime, str, ptrBytes, ptr, len);
+    }
+
     public static void rb_enc_str_buf_cat(ThreadContext context, RubyString str, ByteList ptr, Encoding enc) {
         EncodingUtils.encStrBufCat(context.runtime, str, ptr, enc);
     }