diff --git a/java-collections-maps-3/src/main/java/com/baeldung/map/bytearrays/BytesKey.java b/java-collections-maps-3/src/main/java/com/baeldung/map/bytearrays/BytesKey.java
new file mode 100644
index 0000000000..4bdcfe4b06
--- /dev/null
+++ b/java-collections-maps-3/src/main/java/com/baeldung/map/bytearrays/BytesKey.java
@@ -0,0 +1,28 @@
+package com.baeldung.map.bytearrays;
+
+import java.util.Arrays;
+
+public final class BytesKey {
+    private final byte[] array;
+
+    public BytesKey(byte[] array) {
+        this.array = array;
+    }
+
+    public byte[] getArray() {
+        return array.clone();
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        BytesKey bytesKey = (BytesKey) o;
+        return Arrays.equals(array, bytesKey.array);
+    }
+
+    @Override
+    public int hashCode() {
+        return Arrays.hashCode(array);
+    }
+}
diff --git a/java-collections-maps-3/src/test/java/com/baeldung/map/bytearrays/ByteArrayKeyUnitTest.java b/java-collections-maps-3/src/test/java/com/baeldung/map/bytearrays/ByteArrayKeyUnitTest.java
new file mode 100644
index 0000000000..8f5b89e11e
--- /dev/null
+++ b/java-collections-maps-3/src/test/java/com/baeldung/map/bytearrays/ByteArrayKeyUnitTest.java
@@ -0,0 +1,104 @@
+package com.baeldung.map.bytearrays;
+
+import com.google.common.collect.ImmutableList;
+import org.junit.jupiter.api.Test;
+
+import java.util.Base64;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class ByteArrayKeyUnitTest {
+    @Test
+    void givenPrimitiveByteArrayKey_whenRetrievingFromMap_shouldRetrieveDifferentObjects() {
+        // given
+        byte[] key1 = {1, 2, 3};
+        byte[] key2 = {1, 2, 3};
+        String value1 = "value1";
+        String value2 = "value2";
+        Map<byte[], String> map = new HashMap<>();
+        map.put(key1, value1);
+        map.put(key2, value2);
+
+        // when
+        String retrievedValue1 = map.get(key1);
+        String retrievedValue2 = map.get(key2);
+        String retrievedValue3 = map.get(new byte[]{1, 2, 3});
+
+        // then
+        assertThat(retrievedValue1).isEqualTo(value1);
+        assertThat(retrievedValue2).isEqualTo(value2);
+        assertThat(retrievedValue3).isNull();
+    }
+
+    @Test
+    void givenEncodedStringKey_whenRetrievingFromMap_shouldRetrieveLastPutObject() {
+        // given
+        String key1 = Base64.getEncoder().encodeToString(new byte[]{1, 2, 3});
+        String key2 = Base64.getEncoder().encodeToString(new byte[]{1, 2, 3});
+        String value1 = "value1";
+        String value2 = "value2";
+        Map<String, String> map = new HashMap<>();
+        map.put(key1, value1);
+        map.put(key2, value2);
+
+        // when
+        String retrievedValue1 = map.get(key1);
+        String retrievedValue2 = map.get(key2);
+
+        // then
+        assertThat(key1).isEqualTo(key2);
+        assertThat(retrievedValue1).isEqualTo(value2);
+        assertThat(retrievedValue2).isEqualTo(value2);
+        assertThat(retrievedValue1).isEqualTo(retrievedValue2);
+    }
+
+    @Test
+    void givenByteListKey_whenRetrievingFromMap_shouldRetrieveLastPutObject() {
+        // given
+        List<Byte> key1 = ImmutableList.of((byte)1, (byte)2, (byte)3);
+        List<Byte> key2 = ImmutableList.of((byte)1, (byte)2, (byte)3);
+        String value1 = "value1";
+        String value2 = "value2";
+        Map<List<Byte>, String> map = new HashMap<>();
+        map.put(key1, value1);
+        map.put(key2, value2);
+
+        // when
+        String retrievedValue1 = map.get(key1);
+        String retrievedValue2 = map.get(key2);
+
+        // then
+        assertThat(key1).isEqualTo(key2);
+        assertThat(retrievedValue1).isEqualTo(value2);
+        assertThat(retrievedValue2).isEqualTo(value2);
+        assertThat(retrievedValue1).isEqualTo(retrievedValue2);
+    }
+
+    @Test
+    void givenCustomWrapperKey_whenRetrievingFromMap_shouldRetrieveLastPutObject() {
+        // given
+        BytesKey key1 = new BytesKey(new byte[]{1, 2, 3});
+        BytesKey key2 = new BytesKey(new byte[]{1, 2, 3});
+        String value1 = "value1";
+        String value2 = "value2";
+        Map<BytesKey, String> map = new HashMap<>();
+        map.put(key1, value1);
+        map.put(key2, value2);
+
+        // when
+        String retrievedValue1 = map.get(key1);
+        String retrievedValue2 = map.get(key2);
+        String retrievedValue3 = map.get(new BytesKey(new byte[]{1, 2, 3}));
+
+        // then
+        assertThat(key1).isEqualTo(key2);
+        assertThat(retrievedValue1).isEqualTo(value2);
+        assertThat(retrievedValue2).isEqualTo(value2);
+        assertThat(retrievedValue1).isEqualTo(retrievedValue2);
+        assertThat(retrievedValue3).isEqualTo(value2);
+
+    }
+}