java-8 Questions
2
I was iterating over some files, 5328 to be precise. These files are average XML files with 60-200 lines max. They are first filtered through a simple method isXmlSourceFile that parse the path.
...
3
Solved
There are too much hype about functional programming and particularly the new Java 8 streams API. It is advertised as good replacement for old good loops and imperative paradigm.
Indeed sometimes ...
Latrell asked 14/1, 2018 at 11:0
2
Solved
I was playing around with Java 8 lambdas, method references and interface default methods to explore the wonderful world of currying, and then I got this Java error I cannot understand.
Here is th...
6
Solved
I am new to java 8 and I am trying to get five years before now, here is my code:
Instant fiveYearsBefore = Instant.now().plus(-5,
ChronoUnit.YEARS);
But I get the following error:
java.time.t...
8
Solved
Stream<String> a = Stream.of("one", "three", "five");
Stream<String> b = Stream.of("two", "four", "six");
What do I need to do for the output to be the below?
// one
// two
// thre...
Monkhmer asked 14/11, 2018 at 19:42
9
Solved
In Java, is it possible to have a lambda accept multiple different types?
I.e:
Single variable works:
Function <Integer, Integer> adder = i -> i + 1;
System.out.println (adder.apply (1...
4
Solved
I want to merge huge files containing strings into one file and tried to use nio2. I do not want to load the whole file into memory, so I tried it with BufferedReader:
public void mergeFiles(files...
2
I have a Flux and I want to convert it to List. How can I do that?
Flux<Object> getInstances(String serviceId); // Current one
List<Object> getInstances(String serviceId); // Demande...
Dearing asked 10/6, 2020 at 12:27
7
Solved
I have one computer that I intentionally installed JDK on. I have another computer with JRE, for, among other things, testing. However, when I got a java application working on this computer, and t...
3
Solved
I have a List<LedgerEntry> ledgerEntries and I need to calculate the sums of creditAmount and debitAmount.
class LedgerEntry{
private BigDecimal creditAmount;
private BigDecimal debitAmoun...
Patricio asked 22/2, 2017 at 8:25
8
Solved
Java 8 introduced java.time.Clock which can be used as an argument to many other java.time objects, allowing you to inject a real or fake clock into them. For example, I know you can create a Clock...
Elevenses asked 21/11, 2014 at 17:30
2
Solved
When I am scanning code with sonar lint the following code shows the bug as "The return value of "orElseThrow" must be used"
itemList.stream()
.filter(item -> orderItemId.equals(item.getId()))...
7
Solved
I have a many objects of type Slot in an array list.
Slot class is as shown below-
Slot{
int start;
int end;
}
let the list of type List<Slot> be called slots. The slots are sorted bas...
Skilling asked 24/9, 2015 at 21:43
12
Solved
Java 8 added a new java.time API for working with dates and times (JSR 310).
I have date and time as string (e.g., "2014-04-08 12:30"). How can I obtain a LocalDateTime instance from the ...
11
Solved
Looking for a way to chain optionals so that the first one that is present is returned. If none are present Optional.empty() should be returned.
Assuming I have several methods like this:
Optiona...
Suffuse asked 14/2, 2015 at 10:32
15
Solved
I would like to implement lazy field initialization (or deferred initialization) without an if statement and taking advantage of lambdas. So, I would like to have the same behavior of the following...
Condescend asked 18/3, 2015 at 21:18
6
Solved
I have installed Ubuntu 20.4 LTS on WSL. My windows 10 already have the JDK installed. Do I need to install JDK on ubuntu on WSL or can I use the Windows 10 JDK in the Ubuntu? How you do Java progr...
Warily asked 13/9, 2020 at 3:14
9
I'm having an issue with mockito and powermock, I can mock an abstract class with a final static method with no problems. When trying to mock an Interface as with WebIServerSession I'm getting the ...
Farthing asked 8/11, 2018 at 13:48
6
Solved
I'm trying to deserialize an ISO8601 formatted date into Java8 java.time.Instant using Jackson. I registered JavaTimeModule with the ObjectMapper, and turned off the WRITE_DATES_AS_TIMESTAMPS setti...
9
I want the map to have key as Character and value as Integer, value represents the frequency of the character.
The below code won't compile because I am probably using the wrong signature for...
3
What is the difference between the get() and join() methods of the CompletableFuture<T> class?
Below is the my code:
List<String> process() {
List<String> messages = Arrays.asLi...
Oswaldooswalt asked 3/8, 2017 at 16:51
4
I have below code in one of my methods
ZonedDateTime current = Instant.now().atZone(ZoneId.of(AMERICA_NEW_YORK));
I want to mock current in the JUnit test.
I tried with java.time.Clock but for...
17
Solved
I'm having a small problem with formatting a Java 8 LocalDateTime in my Spring Boot Application. With 'normal' dates I have no problem, but the LocalDateTime fields are converted to the following:
...
Erastianism asked 29/4, 2015 at 23:8
4
Solved
I recently wrote a small app that periodically checked the content of a directory. After a while, the app crashed because of too many open file handles. After some debugging, I found the error in t...
4
This question is not a duplicate of java.lang.NoClassDefFoundError: sun/misc/BASE64Encoder.
I am trying to update the Java Version (to 11) in my app and one of the libraries in my app uses sun.mis...
Whoever asked 4/6, 2020 at 11:17
© 2022 - 2024 — McMap. All rights reserved.