From 9e21e95e6fc6dbf8ce6503b23a7324fa750bc2ef Mon Sep 17 00:00:00 2001
From: Muhammad Asif <muasif80@gmail.com>
Date: Wed, 27 Mar 2024 21:57:34 +0500
Subject: [PATCH] BAEL-7030 Added the example code (#16085)

* BAEL-7030 Added the example code

* Removed public modifier
---
 .../ImmutableCollectionsUnitTest.java         | 54 +++++++++++++++++++
 1 file changed, 54 insertions(+)
 create mode 100644 core-java-modules/core-java-collections-5/src/test/java/com/baeldung/immutables/ImmutableCollectionsUnitTest.java

diff --git a/core-java-modules/core-java-collections-5/src/test/java/com/baeldung/immutables/ImmutableCollectionsUnitTest.java b/core-java-modules/core-java-collections-5/src/test/java/com/baeldung/immutables/ImmutableCollectionsUnitTest.java
new file mode 100644
index 0000000000..6daec6d959
--- /dev/null
+++ b/core-java-modules/core-java-collections-5/src/test/java/com/baeldung/immutables/ImmutableCollectionsUnitTest.java
@@ -0,0 +1,54 @@
+package com.baeldung.immutables;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.junit.jupiter.api.Test;
+
+class ImmutableCollectionsUnitTest {
+
+    @Test
+    void givenUnmodifiableMap_whenPutNewEntry_thenThrowsUnsupportedOperationException() {
+        Map<String, String> modifiableMap = new HashMap<>();
+        modifiableMap.put("name1", "Michael");
+        modifiableMap.put("name2", "Harry");
+
+        Map<String, String> unmodifiableMap = Collections.unmodifiableMap(modifiableMap);
+
+        assertThrows(UnsupportedOperationException.class, () -> unmodifiableMap.put("name3", "Micky"));
+    }
+
+    @Test
+    void givenUnmodifiableMap_whenPutNewEntryUsingOriginalReference_thenSuccess() {
+        Map<String, String> modifiableMap = new HashMap<>();
+        modifiableMap.put("name1", "Michael");
+        modifiableMap.put("name2", "Harry");
+
+        Map<String, String> unmodifiableMap = Collections.unmodifiableMap(modifiableMap);
+        modifiableMap.put("name3", "Micky");
+
+        assertEquals(modifiableMap, unmodifiableMap);
+        assertTrue(unmodifiableMap.containsKey("name3"));
+    }
+
+    @Test
+    void givenImmutableMap_whenPutNewEntry_thenThrowsUnsupportedOperationException() {
+        Map<String, String> immutableMap = Map.of("name1", "Michael", "name2", "Harry");
+
+        assertThrows(UnsupportedOperationException.class, () -> immutableMap.put("name3", "Micky"));
+    }
+
+    @Test
+    void givenImmutableMap_whenUsecopyOf_thenExceptionOnPut() {
+        Map<String, String> immutableMap = Map.of("name1", "Michael", "name2", "Harry");
+        Map<String, String> copyOfImmutableMap = Map.copyOf(immutableMap);
+
+        assertThrows(UnsupportedOperationException.class, () -> copyOfImmutableMap.put("name3", "Micky"));
+    }
+}
+