diff --git a/core-java/src/test/java/com/baeldung/java/doublebrace/DoubleBraceTest.java b/core-java/src/test/java/com/baeldung/java/doublebrace/DoubleBraceTest.java
new file mode 100644
index 0000000000..77d94f6544
--- /dev/null
+++ b/core-java/src/test/java/com/baeldung/java/doublebrace/DoubleBraceTest.java
@@ -0,0 +1,41 @@
+package com.baeldung.java.doublebrace;
+
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Set;
+import java.util.stream.Stream;
+import static java.util.stream.Collectors.toSet;
+import static org.junit.Assert.assertTrue;
+import org.junit.Test;
+
+public class DoubleBraceTest {
+
+    @Test
+    public void whenInitializeSetWithoutDoubleBraces_containsElements() {
+        final Set<String> countries = new HashSet<String>();
+        countries.add("India");
+        countries.add("USSR");
+        countries.add("USA");
+        assertTrue(countries.contains("India"));
+    }
+
+    @Test
+    public void whenInitializeSetWithDoubleBraces_containsElements() {
+        final Set<String> countries = new HashSet<String>() {
+
+            {
+                add("India");
+                add("USSR");
+                add("USA");
+            }
+        };
+        assertTrue(countries.contains("India"));
+    }
+
+    @Test
+    public void whenInitializeUnmodifiableSetWithDoubleBrace_containsElements() {
+        final Set<String> countries = Collections.unmodifiableSet(Stream.of("India", "USSR", "USA").collect(toSet()));
+        assertTrue(countries.contains("India"));
+    }
+
+}