--- /dev/null
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+class Test {
+
+ void foo(Stream<String> pairStream) {
+ Map<String, Map<String, Integer>> frequencyMap = pairStream
+ .collect(Collectors.toMap(p -> p, p -> of(p, 1), (m1, m2) -> new HashMap<>(m1)));
+
+ Map<String, Map<String, Integer>> frequencyMap1 = pairStream
+ .collect(Collectors.toMap(p -> p, p -> of(p, 1), (m1, m2) -> new HashMap<>()));
+ }
+
+ public static <K, V> Map<K, V> of(K k1, V v1) {
+ return null;
+ }
+}
\ No newline at end of file