Merge pull request #14520 from sam-gardner/BAEL-6837-get-first-item-from-set

BAEL-6837 Add example code for getting the first item from a Set

core-java-modules/core-java-collections-set-2/src/test/java/com/baeldung/firstitemfromset/GetFirstItemFromSetUnitTest.java

@@ -0,0 +1,35 @@
+package com.baeldung.firstitemfromset;
+
+import static org.junit.Assert.assertEquals;
+
+import java.util.Arrays;
+import java.util.Iterator;
+import java.util.LinkedHashSet;
+import java.util.Optional;
+import java.util.Set;
+
+import org.junit.Test;
+
+public class GetFirstItemFromSetUnitTest {
+
+    @Test
+    public void givenASet_whenUsingIterator_thenRetrieveAnItem(){
+        Set<Integer> set = new LinkedHashSet<>(Arrays.asList(1, 2, 3, 4, 5));
+        Iterator iterator = set.iterator();
+        if(iterator.hasNext()){
+            int retrieved = (int) iterator.next();
+            assertEquals(retrieved, 1);
+        }
+    }
+
+    @Test
+    public void givenASet_whenUsingStreams_thenRetrieveAnItem(){
+        Set<Integer> set = new LinkedHashSet<>(Arrays.asList(1, 2, 3, 4, 5));
+        Optional<Integer> optional = set.stream().findFirst();
+        if(optional.isPresent()){
+            int retrieved = optional.get();
+            assertEquals(retrieved, 1);
+        }
+    }
+
+}