All Questions
333 questions
1
vote
0
answers
49
views
Why do I need to specify the types of the Map.Entry. Is it because the types of the keys are different? [duplicate]
The following code results in the error:
Non-static method cannot be referenced from a static context
public static Optional<String> getAuthorWithMostPublishedBooks(){
return books.stream()...
0
votes
0
answers
34
views
Java Stream API memory consumption of multiple .filter() in chain [duplicate]
Have a question regarding .filter (or any other non-terminal) methods in Stream API chain (code in the block below is just for example):
var s1 = Stream.of(1,2,3,4,5,6,7,8,9);
var intemidiate1 = s1....
-1
votes
1
answer
158
views
Could Java stream create memory overhead [closed]
What I got from basic principle of Java streams is that it works on immutable objects and does operation and collect (if we collect it as collection) as new immutable objects.
Does that means for any ...
- 895
0
votes
0
answers
113
views
How to use Stream.collect with specific class as suplider
I am a student.
You might think I'm overloading the code with this, unnecessarily, but the goal is just to improve the understanding of the collect method. So all these components that I mention are ...
-1
votes
1
answer
86
views
Transforming Java POJOs and nested streams(Java 8), with possibility of null inner stream
Say I have following java POJOs
class Outer {
Config;
List<Warning> warnings;
}
class Config {
String configId;
String configName;
}
class Warning {
String warningId;
String ...
- 2,633
-3
votes
1
answer
75
views
Setting up different Java class fields value by a single value on some counter value [closed]
Setting up different Java class fields value by a single value on some counter value?
In a Java class, having similar kind of fields like:
public class User {
private String user_Id_1;
private ...
- 709
1
vote
1
answer
111
views
Grouping by multiple fields and counting using in Java 8
I have a Person table in database and the associated domain class looks like below:
public class Person {
private String firstName;
private String secondName;
private String city;
...
- 366
-1
votes
1
answer
146
views
Converting nested loop into idiomatic Java 8 stream operators
The following legacy logic needs to be converted into Java 8 functional approach:
AchFile dataRoot = unmarshalled.stream().findFirst().get();
List<AchBatch> batches = dataRoot....
- 19.1k
0
votes
1
answer
65
views
How to use an if statement in a Java stream to avoid a duplicate stream process
Here is my code from the Java MOOC.fi course where I am learning about streams. The code below works but the way I wrote it is quite amateur. I was thinking of somehow integrating an if statement in ...
- 3
0
votes
1
answer
55
views
Can't get reducer stream to work in Java. What's wrong with my code?
I want to use a reducer to sum up all the inputs from 'args', then divide by the args length to get the result I'm looking for (just a simple function to learn java).
I'm following (as far as I can ...
3
votes
3
answers
1k
views
Java Stream Methods vs foreach
I have a teammate that did all his stream operations in a foreach execution. I tried to come up with advantages of using the filter, map and to list methods instead.
What are other advantages it has ...
- 119
0
votes
1
answer
539
views
Getting List of Integers from List of Array of Objects
I have my resultset in List of array of objects. I want to get values in an Integer list using java stream.
List<Object[]> to List<Integer> in java8.
I was trying to achieve like this....
1
vote
1
answer
320
views
How to declare Comparator using Java 8 syntax?
I have a 2D array of type int i.e [][]intervals
Using Java 8 syntax, I can sort like this
Arrays.sort(intervals, (int[] o1, int[] o2) -> {
if (o1[1] != o2[1]) return o1[1] - o2[1];
return ...
- 2,633
6
votes
3
answers
2k
views
Java Stream : How to filter conditionally?
I have the following stream statement with Java Stream and I filter records based on the typeId values as types.getIds().contains(x.getType().getId()):
return petRepository.findAll().stream()
...
user21348253
0
votes
1
answer
161
views
Functional Programing; using streams to create a set/ list of objects in java
the object of this specific function is to create a list of (competitor objects ) Using 2 lists containing time and names.
note that this is a trail to convert from object oriented to functional ...
