java-8 Questions
10
Solved
What is the easiest/shortest way to convert a Java 8 Stream into an array?
Semaphore asked 15/4, 2014 at 9:0
2
From a simple point of view, lambda expressions are compiled into static methods, since they don’t capture this (i.e. do not access instance members).
public class App {
public static void foo()...
4
I'm trying to use Java 1.8 with lambda expressions with Idea UI Designer, I have in maven:
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>ideauidesigner-maven-...
4
Solved
I'm looking for a concise way to filter out items in a List at a particular index. My example input looks like this:
List<Double> originalList = Arrays.asList(0.0, 1.0, 2.0, 3.0, 4.0, 5.0, 6...
Ebarta asked 29/3, 2016 at 20:1
4
Solved
I have POJO definition as follows:
class EmployeeDetails{
private String deptName;
private Double salary;
private Double bonus;
...
}
Currently, i have lambda expression for Group By 'deptNa...
3
Solved
I have something like this:
Integer totalIncome = carDealer.getBrands().stream().mapToInt(brand -> brand.getManufacturer().getIncome()).sum();
Integer totalOutcome = carDealer.getBrands().strea...
Carbonic asked 16/11, 2017 at 18:43
7
Solved
Is there a way in Java's Stream API to map first element of stream differently than other?
Equivalent of this code:
List<Bar> barList = new ArrayList<>();
for (int i=0; i<fooList....
Overrule asked 23/3, 2018 at 18:13
2
Solved
I'm calling an async client method by streaming over a list of objects. The method returns Future.
What's the best way to iterate over the list of Futures returned after the call (so as to process...
Umbles asked 5/4, 2017 at 8:55
3
Solved
I'm implementing some new features of Java 8 on my desktop app and Hibernate 3.6 seems to doesn't like it.
I added to an Interface a "default method", since then Hibernate it throwing:
2014-10-02...
10
Solved
How can I get the last element of a stream or list in the following code?
Where data.careas is a List<CArea>:
CArea first = data.careas.stream()
.filter(c -> c.bbox.orientationHorizonta...
Clerc asked 29/1, 2014 at 9:25
16
Solved
In Java 8, methods can be created as Lambda expressions and can be passed by reference (with a little work under the hood). There are plenty of examples online with lambdas being created and used w...
2
Solved
Which one is better in terms of performance?
finalWords.stream().forEach(word -> stringBuilder.append(word).append(”,“));
String finalResult = stringBuilder.toString();
VS
String finalRes...
Mouser asked 4/5, 2018 at 14:32
4
Solved
I want to sort String elements in the array months by length using Arrays.sort method. I was told here, that it's possible to use lambda expressions instead of creating new class implementing Compa...
3
final List<Toy> toys = Arrays.asList("new Toy(1)", "new Toy(2)");
final List<Item> itemList = toys.stream()
.map(toy -> {
return Item.from(toy); //Creates Item type
}).collect(C...
Freespoken asked 22/5, 2017 at 12:56
4
Solved
Say I have a list of Lists..
List<List<String>> lists = new ArrayList<>();
Is there a clever lambda way to collapse this into a List of all the contents ?
14
Solved
In Java 8, you can use a method reference to filter a stream, for example:
Stream<String> s = ...;
long emptyStrings = s.filter(String::isEmpty).count();
Is there a way to create a method ...
2
Solved
I have little maven project that uses com.sun.istack.internal.Nullable.
I tried both JDK 9 and 1.8, and still get error about package does not exists.
I search for the package and find some: https:...
Dysphoria asked 13/12, 2017 at 12:39
2
Solved
Since the introduction of Java 8, is Hibernate waiting some changes?
specially
Is there any way to write queries with lambdas in Hibernate? (i.e. like a .net Linq-to-SQL style)
If not, when it's...
2
Solved
I am trying to use @CreationTimestamp and @UpdateTimestamp with LocalDateTime type, but it is giving me org.hibernate.HibernateException: Unsupported property type for generator annotation @Creatio...
Dunfermline asked 6/11, 2018 at 12:13
4
Solved
What is the Java 8 functional interface for a method that takes nothing and returns nothing?
I.e., the equivalent to the C# parameterless Action with void return type?
Palaeozoology asked 26/5, 2014 at 11:8
8
Solved
In Java 8, this works:
Stream<Class> stream = Stream.of(ArrayList.class);
HashMap<Class, List<Class>> map = (HashMap)stream.collect(Collectors.groupingBy(Class::getSuperclass));
...
Raised asked 25/3, 2014 at 3:45
6
I have JSONs with a date-time attribute in the format "2014-03-10T18:46:40.000Z", which I want to deserialize into a java.time.LocalDateTime field using Gson.
When I tried to deserialize, I get th...
11
Solved
In my test case, I need test time sensitive method, in that method we're using java 8 class LocalDate, it is not Joda.
What can I do to change time, when I'm running test
Adrianople asked 25/9, 2015 at 23:26
13
Solved
I have noted that many Java 8 methods in Oracle JDK use Objects.requireNonNull(), which internally throws NullPointerException if the given object (argument) is null.
public static <T> T req...
Yoakum asked 11/8, 2017 at 10:26
4
Solved
I'm trying to apply my knowledge of streams to some leetcode algorithm questions. Here is a general summary of the question:
Given a string which contains only lowercase letters, remove duplicate
...
Allocate asked 22/8, 2020 at 3:18
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