--- jna-5.13.0/build.xml	2023-05-30 15:30:31.116195853 +0200
+++ jna-5.13.0/build.xml	2023-05-30 15:31:56.400786710 +0200
@@ -106,8 +106,14 @@
     JDK 11 is the last JDK, that supports creation of Java 6 compatible class
     files.
   -->
-  <condition property="compatibility" value="1.6" else="9">
+  <condition property="compatibility" value="1.8" else="9">
+    <or>
     <matches pattern="^1\.\d+$" string="${ant.java.version}"/>
+        <matches pattern="^9.*$" string="${ant.java.version}"/>
+        <matches pattern="^1.*$$" string="${ant.java.version}"/>
+        <matches pattern="^20.*$$" string="${ant.java.version}"/>
+        <matches pattern="^21.*$$" string="${ant.java.version}"/>
+    </or>
   </condition>
 
   <condition property="compatibility-check" value="true">
--- jna-5.13.0/contrib/platform/src/com/sun/jna/platform/mac/XAttrUtil.java	2023-05-30 15:30:31.140196020 +0200
+++ jna-5.13.0/contrib/platform/src/com/sun/jna/platform/mac/XAttrUtil.java	2023-05-30 15:30:47.452309013 +0200
@@ -23,6 +23,7 @@
  */
 package com.sun.jna.platform.mac;
 
+import java.nio.Buffer;
 import java.nio.ByteBuffer;
 import java.nio.charset.Charset;
 import java.util.ArrayList;
@@ -102,11 +103,11 @@
         bb.mark(); // first key starts from here
         while (bb.hasRemaining()) {
             if (bb.get() == 0) {
-                ByteBuffer nameBuffer = (ByteBuffer) bb.duplicate().limit(bb.position() - 1).reset();
+                ByteBuffer nameBuffer = (ByteBuffer) ((Buffer)(bb.duplicate())).limit(bb.position() - 1).reset();
                 if (nameBuffer.hasRemaining()) {
                     names.add(decodeString(nameBuffer));
                 }
-                bb.mark(); // next key starts from here
+                ((Buffer)bb).mark(); // next key starts from here
             }
         }
 
--- jna-5.13.0/test/com/sun/jna/BufferArgumentsMarshalTest.java	2023-05-30 15:30:31.288197044 +0200
+++ jna-5.13.0/test/com/sun/jna/BufferArgumentsMarshalTest.java	2023-05-30 15:30:47.452309013 +0200
@@ -23,6 +23,7 @@
  */
 package com.sun.jna;
 
+import java.nio.Buffer;
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
 import java.nio.DoubleBuffer;
@@ -108,7 +109,7 @@
         for (int i=0;i < buf.capacity();i++) {
             assertEquals("Bad value at index " + i, MAGIC, buf.get(i));
         }
-        buf.position(512);
+        ((Buffer)buf).position(512);
         lib.fillInt8Buffer(buf, 512, (byte)0);
         for (int i=0;i < buf.capacity();i++) {
             assertEquals("Bad value at index " + i,
--- jna-5.13.0/test/com/sun/jna/PerformanceTest.java	2023-05-30 15:30:31.288197044 +0200
+++ jna-5.13.0/test/com/sun/jna/PerformanceTest.java	2023-05-30 15:30:47.452309013 +0200
@@ -396,7 +396,7 @@
         start = System.currentTimeMillis();
         for (int i=0;i < COUNT;i++) {
             byte[] bytes = str.getBytes();
-            b.position(0);
+            ((Buffer)b).position(0);
             b.put(bytes);
             b.put((byte)0);
             int iresult = CLibrary.strlen(b);
@@ -413,7 +413,7 @@
             for (int i=0;i < COUNT;i++) {
                 b.putInt(8, (int)pb.peer + 12);
                 b.putInt(12, (int)pb.peer + 16);
-                b.position(16);
+                ((Buffer)b).position(16);
                 // This operation is very expensive!
                 b.put(str.getBytes());
                 b.put((byte)0);
@@ -454,7 +454,7 @@
 
         start = System.currentTimeMillis();
         for (int i=0;i < COUNT;i++) {
-            b.position(0);
+            ((Buffer)b).position(0);
             b.put(bulk);
         }
         delta = System.currentTimeMillis() - start;
--- jna-5.13.0/test/com/sun/jna/PointerBufferTest.java	2023-05-30 15:30:31.288197044 +0200
+++ jna-5.13.0/test/com/sun/jna/PointerBufferTest.java	2023-05-30 15:30:47.452309013 +0200
@@ -24,6 +24,7 @@
 
 package com.sun.jna;
 
+import java.nio.Buffer;
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
 import java.nio.DoubleBuffer;
@@ -42,7 +43,7 @@
         final String ENCODING = "utf8";
         Memory m = new Memory(1024);
         ByteBuffer buf = m.getByteBuffer(0, m.size()).order(ByteOrder.nativeOrder());
-        buf.put(MAGIC.getBytes(ENCODING)).put((byte) 0).flip();
+        ((Buffer)(buf.put(MAGIC.getBytes(ENCODING)).put((byte) 0))).flip();
         assertEquals("String not written to memory", MAGIC,
                      m.getString(0, ENCODING));
     }
@@ -50,7 +51,7 @@
         final byte MAGIC = (byte)0xED;
         Memory m = new Memory(8);
         ByteBuffer buf = m.getByteBuffer(0, m.size()).order(ByteOrder.nativeOrder());
-        buf.put(MAGIC).flip();
+        ((Buffer)(buf.put(MAGIC))).flip();
         assertEquals("Byte not written to memory", MAGIC,
                 m.getByte(0));
     }
@@ -58,7 +59,7 @@
         final int MAGIC = 0xABEDCF23;
         Memory m = new Memory(8);
         ByteBuffer buf = m.getByteBuffer(0, m.size()).order(ByteOrder.nativeOrder());
-        buf.putInt(MAGIC).flip();
+        ((Buffer)(buf.putInt(MAGIC))).flip();
         assertEquals("Int not written to memory", MAGIC,
                 m.getInt(0));
     }
@@ -66,7 +67,7 @@
         final long MAGIC = 0x1234567887654321L;
         Memory m = new Memory(8);
         ByteBuffer buf = m.getByteBuffer(0, m.size()).order(ByteOrder.nativeOrder());
-        buf.putLong(MAGIC).flip();
+        ((Buffer)(buf.putLong(MAGIC))).flip();
         assertEquals("Long not written to memory", MAGIC,
                 m.getLong(0));
     }