Examples for java stream api

java-8/stream-api/ExampleStreamConversion.java

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+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+public class ExampleStreamConversion {
+        public static void main(String[] args) {
+            //stream to list
+            //1
+            Stream<Integer> numStream = Stream.of(1,2,3,4,5,6,7);
+            List<Integer> numList = numStream.collect(Collectors.toList());
+            System.out.println(numList);
+
+            //2
+            numStream = Stream.of(1,2,3,4,5,6,7);
+            List<Integer> numList1  = numStream.collect(Collectors.toCollection(ArrayList::new));
+
+            //3
+            Stream<Integer> numStream2 = Stream.of(1,2,3,4,5,6,7);
+            List<Integer> numList2 = new ArrayList<>();
+            numStream2.forEach(numList::add);
+
+            //stream to map
+            Stream<String[]> mapStream = Stream.of(new String[][]{{"1", "one"}, {"2", "two"}});
+            Map<String, String> finalMap = mapStream.collect(Collectors.toMap(e -> e[0], e -> e[1]));
+            System.out.println(finalMap);
+
+            //stream to array
+            //1
+            Stream<Integer> intStream = Stream.of(1, 2, 3, 4, 5, 6);
+            Integer[] intArray = intStream.toArray(Integer[]::new);
+            System.out.println(Arrays.toString(intArray));
+
+            //2
+            Stream<Integer> intStream2 = Stream.of(1, 2, 3, 4, 5, 6);
+            int[] intArray2 = intStream2.mapToInt(i -> i).toArray();
+        }
+}