diff --git a/test/org/apache/catalina/util/TestParameterMap.java b/test/org/apache/catalina/util/TestParameterMap.java
index 87ead7f60243..92d801a32b88 100644
--- a/test/org/apache/catalina/util/TestParameterMap.java
+++ b/test/org/apache/catalina/util/TestParameterMap.java
@@ -300,11 +300,37 @@ public void testEntrySetImmutabilityAfterLocked() {
             Assert.fail("ParameterMap is not locked.");
         } catch (UnsupportedOperationException expectedException) {
         }
-
         try {
             entrySet.clear();
             Assert.fail("ParameterMap is not locked.");
         } catch (UnsupportedOperationException expectedException) {
         }
     }
+    @Test
+    public void testComputeIfAbsentAfterLocked() {
+        ((ParameterMap<String, String[]>) paramMap).setLocked(true);
+
+        try {
+            paramMap.computeIfAbsent("param5", k -> new String[]{"value5"});
+            Assert.fail("ParameterMap is not locked.");
+        } catch (IllegalStateException expectedException) {
+        }
+    }
+
+    @Test
+    public void testComputeAfterLocked() {
+        ((ParameterMap<String, String[]>) paramMap).setLocked(true);
+
+        try {
+            paramMap.compute("param1", (k, v) -> new String[]{"changed"});
+            Assert.fail("ParameterMap is not locked.");
+        } catch (IllegalStateException expectedException) {
+        }
+    }
+
+    @Test
+    public void testEmptyParameterMap() {
+        Map<String,String[]> map = new ParameterMap<>();
+        Assert.assertTrue(map.isEmpty());
+    }
 }
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