diff --git a/ext/puma_http11/org/jruby/puma/MiniSSL.java b/ext/puma_http11/org/jruby/puma/MiniSSL.java
index a18c1273..53c75c1b 100644
--- a/ext/puma_http11/org/jruby/puma/MiniSSL.java
+++ b/ext/puma_http11/org/jruby/puma/MiniSSL.java
@@ -23,6 +23,7 @@ import javax.net.ssl.SSLPeerUnverifiedException;
 import javax.net.ssl.SSLSession;
 import java.io.FileInputStream;
 import java.io.IOException;
+import java.nio.Buffer;
 import java.nio.ByteBuffer;
 import java.security.KeyManagementException;
 import java.security.KeyStore;
@@ -65,7 +66,7 @@ public class MiniSSL extends RubyObject {
 
     public void clear() { buffer.clear(); }
     public void compact() { buffer.compact(); }
-    public void flip() { buffer.flip(); }
+    public void flip() { ((Buffer) buffer).flip(); }
     public boolean hasRemaining() { return buffer.hasRemaining(); }
     public int position() { return buffer.position(); }
 
@@ -89,7 +90,7 @@ public class MiniSSL extends RubyObject {
     public void resize(int newCapacity) {
       if (newCapacity > buffer.capacity()) {
         ByteBuffer dstTmp = ByteBuffer.allocate(newCapacity);
-        buffer.flip();
+        flip();
         dstTmp.put(buffer);
         buffer = dstTmp;
       } else {
@@ -101,7 +102,7 @@ public class MiniSSL extends RubyObject {
      * Drains the buffer to a ByteList, or returns null for an empty buffer
      */
     public ByteList asByteList() {
-      buffer.flip();
+      flip();
       if (!buffer.hasRemaining()) {
         buffer.clear();
         return null;