adding new article BAEL-7497 source codes

core-java-modules/core-java-collections-6/README.md

@@ -3,3 +3,5 @@
 ## Core Java Collections Cookbooks and Examples
 
 ### Relevant Articles:
+
+- More articles: [[<-- prev]](/core-java-modules/core-java-collections-5)

core-java-modules/core-java-collections-6/src/test/java/com/baeldung/iteratorvsforeach/IteratorVsForeachUnitTest.java

@@ -0,0 +1,69 @@
+package com.baeldung.iteratorvsforeach;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertIterableEquals;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.List;
+import java.util.stream.Stream;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+class IteratorVsForeachUnitTest {
+
+  private static Stream<Arguments> listProvider() {
+    return Stream.of(
+        Arguments.of(
+            List.of("String1", "String2", "unwanted"),
+            List.of("String1", "String2"))
+    );
+  }
+
+  @Test
+  public void givenEmptyCollection_whenUsingForEach_thenNoElementsAreIterated() {
+    List<String> names = Collections.emptyList();
+    StringBuilder stringBuilder = new StringBuilder();
+    names.forEach(stringBuilder::append);
+    assertEquals("", stringBuilder.toString());
+  }
+
+  @ParameterizedTest
+  @MethodSource("listProvider")
+  public void givenCollectionWithElements_whenRemovingElementDuringForEachIteration_thenElementIsRemoved(
+      List<String> input, List<String> expected) {
+    List<String> mutableList = new ArrayList<>(input);
+    // Separate collection for items to be removed
+    List<String> toRemove = new ArrayList<>();
+
+    // Using forEach to identify items to remove
+    input.forEach(item -> {
+      if (item.equals("unwanted")) {
+        toRemove.add(item);
+      }
+    });
+
+    // Removing the identified items from the original list
+    mutableList.removeAll(toRemove);
+    assertIterableEquals(expected, mutableList);
+  }
+
+  @ParameterizedTest
+  @MethodSource("listProvider")
+  public void givenCollectionWithElements_whenRemovingElementDuringIteratorIteration_thenElementIsRemoved(
+      List<String> input, List<String> expected) {
+    List<String> mutableList = new ArrayList<>(input);
+    Iterator<String> it = mutableList.iterator();
+    while (it.hasNext()) {
+      String item = it.next();
+      if (item.equals("unwanted")) {
+        it.remove(); // Safely remove item
+      }
+    }
+    assertIterableEquals(expected, mutableList);
+  }
+
+}