Demonstrate Java 8 Streams With Collectors

Java Streams/src/EnterTheCollector.java

@@ -1,7 +1,11 @@
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
 
 import static java.util.Comparator.comparingInt;
+import static java.util.stream.Collectors.counting;
+import static java.util.stream.Collectors.groupingBy;
 
 public class EnterTheCollector {
     public static void main(String[] args) {
@@ -22,5 +26,32 @@ public class EnterTheCollector {
                 .filter(product -> product.getWeight() < 30)
                 .sorted(comparingInt(StreamProduct::getWeight))
                 .forEach(System.out::println);
+
+        // Printing out list
+        List<StreamProduct> lightProducts = streamProducts
+                .stream()
+                .filter(streamProduct -> streamProduct.getWeight() < 30)
+                .sorted(comparingInt(StreamProduct::getWeight))
+                .collect(Collectors.toList());
+
+        System.out.println(lightProducts);
+
+        // Mapping the name of the products to product(s) itself
+        Map<String, List<StreamProduct>> lightProducts1 = streamProducts
+                .stream()
+                .filter(streamProduct -> streamProduct.getWeight() < 30)
+                .sorted(comparingInt(StreamProduct::getWeight))
+                .collect(groupingBy(StreamProduct::getName));
+
+        System.out.println(lightProducts1);
+
+        // Using 1 or more collectors on the data
+        Map<String, Long> lightProducts2 = streamProducts
+                .stream()
+                .filter(streamProduct -> streamProduct.getWeight() < 30)
+                .sorted(comparingInt(StreamProduct::getWeight))
+                .collect(groupingBy(StreamProduct::getName, counting()));
+
+        System.out.println(lightProducts2);
     }
 }