Table of contents

1. Optionals
2. Streams
   1. Map and Collect
   2. ConcurrentHashMap and LinkedList
   3. Map to String
3. Sealed Classes
4. Pattern Matching
   1. Scope of Variables
5. Records
6. Text Block (String)
7. Switch (Case)
8. Local Variable Type Interface (Var)
   1. var with lambda
9. Private Interface Methods
10. Try
11. Diamond Operator
    1. For Anonymous Inner Class

---

Optionals

public class OptEx {
    Optional<Map<String, String>> aorMap = Optional.ofNullable(this.customAORMap);

}

Streams

Map and Collect

public class MapExample {

    Map newMap = clientEntityMap.entrySet().stream().collect(Collectors.toMap(Map.Entry::getKey, entry -> entry.getValue().stream().map(e -> {
        String externalCode = e.getDescription();
        String externalCode = e.getDescription();
        String externalCode = e.getDescription();

        return Map.of("externalCode", "");
    }).collect(Collectors.toList())));
}

ConcurrentHashMap and LinkedList

public class LinkedListEx {
    Map newMap = this.clientEntityMap.entrySet()
                                     .stream()
                                     .map(entry -> Map.entry(entry.getKey(), entry.getValue()
                                                                                  .stream()
                                                                                  .map(ClientEntityDetails::toMap)
                                                                                  .collect(Collectors.toCollection(LinkedList::new))))
                                     .collect(Collectors.toConcurrentMap(Map.Entry::getKey, Map.Entry::getValue, (a, b) -> b, ConcurrentHashMap::new));

}

Map to String

public class MapToString {
    Map mapToString = this.clientEntityMap.entrySet()
                                          .stream()
                                          .map(entry -> Map.entry(entry.getKey(), entry.getValue()
                                                                                       .stream()
                                                                                       .map(ClientEntityDetails::toMap)
                                                                                       .collect(Collectors.toCollection(LinkedList::new))))
                                          .collect(Collectors.toConcurrentMap(Map.Entry::getKey, Map.Entry::getValue, (a, b) -> b, ConcurrentHashMap::new));

}

Sealed Classes

Pattern Matching

Scope of Variables

Records

Text Block (String)

Switch (Case)

Local Variable Type Interface (Var)

var with lambda

Private Interface Methods

Try

Diamond Operator

For Anonymous Inner Class