Core Java for loop test

core-java-modules/core-java-8/src/test/java/com/ossez/java8/Java8ForEachUnitTest.java

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+package com.ossez.java8;
+
+import java.util.*;
+import java.util.function.Consumer;
+
+
+import com.google.common.collect.Lists;
+import org.junit.jupiter.api.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class Java8ForEachUnitTest {
+
+    private static final Logger logger = LoggerFactory.getLogger(Java8ForEachUnitTest.class);
+
+    @Test
+    public void compareForEachMethods_thenPrintResults() {
+
+        List<String> names = new ArrayList<>();
+        names.add("Larry");
+        names.add("Steve");
+        names.add("James");
+        names.add("Conan");
+        names.add("Ellen");
+
+        // Java 5 - for-loop
+        logger.debug("--- Enhanced for-loop ---");
+        for (String name : names) {
+            logger.debug(name);
+        }
+
+        // Java 8 - forEach
+        names.forEach(name -> {
+            System.out.println(name);
+        });
+
+        logger.debug("--- Print Consumer ---");
+        Consumer<String> printConsumer = new Consumer<String>() {
+            public void accept(String name) {
+                System.out.println(name);
+            }
+
+            ;
+        };
+
+        names.forEach(printConsumer);
+
+        // Anonymous inner class that implements Consumer interface
+        logger.debug("--- Anonymous inner class ---");
+        names.forEach(new Consumer<String>() {
+            public void accept(String name) {
+                logger.debug(name);
+            }
+        });
+
+        // Java 8 - forEach - Lambda Syntax
+        logger.debug("--- forEach method ---");
+        names.forEach(name -> logger.debug(name));
+
+        // Java 8 - forEach - Print elements using a Method Reference
+        logger.debug("--- Method Reference ---");
+        names.forEach(logger::debug);
+    }
+
+    @Test
+    public void givenList_thenIterateAndPrintResults() {
+        List<String> names = Arrays.asList("Larry", "Steve", "James");
+
+        names.forEach(System.out::println);
+    }
+
+    @Test
+    public void givenSet_thenIterateAndPrintResults() {
+        Set<String> uniqueNames = new HashSet<>(Arrays.asList("Larry", "Steve", "James"));
+
+        uniqueNames.forEach(System.out::println);
+    }
+
+    @Test
+    public void givenQueue_thenIterateAndPrintResults() {
+        Queue<String> namesQueue = new ArrayDeque<>(Arrays.asList("Larry", "Steve", "James"));
+
+        namesQueue.forEach(System.out::println);
+    }
+
+    @Test
+    public void givenMap_thenIterateAndPrintResults() {
+        Map<Integer, String> namesMap = new HashMap<>();
+        namesMap.put(1, "Larry");
+        namesMap.put(2, "Steve");
+        namesMap.put(3, "James");
+
+        namesMap.entrySet()
+                .forEach(entry -> System.out.println(entry.getKey() + " " + entry.getValue()));
+    }
+
+    @Test
+    public void givenMap_whenUsingBiConsumer_thenIterateAndPrintResults2() {
+        Map<Integer, String> namesMap = new HashMap<>();
+        namesMap.put(1, "Larry");
+        namesMap.put(2, "Steve");
+        namesMap.put(3, "James");
+
+        namesMap.forEach((key, value) -> System.out.println(key + " " + value));
+    }
+
+    @Test
+    public void testIteratorAndFor() {
+        List<String> testList = Arrays.asList("A", "B", "C");
+
+        Iterator iterator = testList.iterator();
+        while (iterator.hasNext()) {
+            logger.debug((String) iterator.next());
+
+        }
+        
+        logger.debug("--- FOR ---");
+        for (int i = 0; i < testList.size(); i++) {
+            logger.debug("{} > {}", i, testList.get(i));
+        }
+
+        logger.debug("--- FOR LOOP ---");
+        for (String s : testList) {
+            logger.debug(s);
+        }
+
+        logger.debug("--- FOR EACH ---");
+        testList.forEach(s -> {
+            logger.debug(s);
+        });
+    }
+
+}