diff --git a/api/src/test/java/jakarta/mail/internet/ParameterListTest.java b/api/src/test/java/jakarta/mail/internet/ParameterListTest.java
index 9f7ad0d2..a015da66 100644
--- a/api/src/test/java/jakarta/mail/internet/ParameterListTest.java
+++ b/api/src/test/java/jakarta/mail/internet/ParameterListTest.java
@@ -41,7 +41,7 @@ public static void before() {
     public void testBackslash() throws Exception {
         System.clearProperty("mail.mime.windowsfilenames");
         ParameterList pl = new ParameterList("; filename=\"\\a\\b\\c.txt\"");
-        assertEquals(pl.get("filename"), "abc.txt");
+        assertEquals("abc.txt", pl.get("filename"));
     }
 
     /**
@@ -71,4 +71,33 @@ public void testLongSet() throws Exception {
         assertTrue(pls.indexOf("p*0=") >= 0);
         assertTrue(pls.indexOf("p*1=") >= 0);
     }
+
+    @Test
+    public void testUtf8() throws Exception {
+        String disposition = ";\n" +
+                             " filename*0*=utf-8''XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX--111111111-XXXXXXXXXXX;\n" +
+                             " filename*1*=XXXXXXXXXXXXXXXXXXXXXXXXXXX.pdf";
+        ParameterList parameterList = new ParameterList(disposition);
+        assertEquals("XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX--111111111-XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX.pdf", parameterList.get("filename"));
+    }
+
+    @Test
+    public void testQEncoding() throws Exception {
+        String disposition = ";\n" +
+                             " filename==?utf-8?Q?XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX--111111111-XXXXXXXXXXXXXXXXXXX?=\n" +
+                             " =?utf-8?Q?XXXXXXXXXXXXXXXXXXX=2Epdf?=;";
+        ParameterList parameterList = new ParameterList(disposition);
+        assertEquals("XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX--111111111-XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX.pdf", parameterList.get("filename"));
+    }
+    
+    @Test
+    public void testQEncodingAndUtf8() throws Exception {
+        String disposition = ";\n" +
+                             " filename==?utf-8?Q?XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX--111111111-XXXXXXXXXXXXXXXXXXX?=\n" +
+                             " =?utf-8?Q?XXXXXXXXXXXXXXXXXXX=2Epdf?=;\n" +
+                             " filename*0*=utf-8''XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX--111111111-XXXXXXXXXXX;\n" +
+                             " filename*1*=XXXXXXXXXXXXXXXXXXXXXXXXXXX.pdf";
+        ParameterList parameterList = new ParameterList(disposition);
+        assertEquals("XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX--111111111-XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX.pdf", parameterList.get("filename"));
+    }
 }