java-8 Archives - Page 4 of 11

Difference between CompletableFuture, Future and RxJava’s Observable

I would like to know the difference between CompletableFuture,Future and Observable RxJava. What I know is all are asynchronous but Future.get() blocks the ...

May 22, 2022
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Using streams to convert a list of objects into a string obtained from the toString method

There are a lot of useful new things in Java 8. E.g., I can iterate with a stream over a list of objects ...

May 21, 2022
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Java8: HashMap to HashMap using Stream / Map-Reduce / Collector

I know how to “transform” a simple Java List from Y -> Z, i.e.: List<String> x; List<Integer> y = x.stream() .map(s -> Integer.parseInt(s)) ...

May 21, 2022
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Why does Iterable not provide stream() and parallelStream() methods?

I am wondering why the Iterable interface does not provide the stream() and parallelStream() methods. Consider the following class: public class Hand implements ...

May 21, 2022
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Difference between `Optional.orElse()` and `Optional.orElseGet()`

I am trying to understand the difference between the Optional<T>.orElse() and Optional<T>.orElseGet() methods. The description for the orElse() method is “Return the value ...

May 20, 2022
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Java 8 lambda Void argument

Let’s say I have the following functional interface in Java 8: interface Action<T, U> { U execute(T t); } And for some cases ...

May 19, 2022
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Using Java 8’s Optional with Stream::flatMap

The new Java 8 stream framework and friends make for some very concise Java code, but I have come across a seemingly-simple situation ...

May 18, 2022
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Filter Java Stream to 1 and only 1 element

I am trying to use Java 8 Streams to find elements in a LinkedList. I want to guarantee, however, that there is one ...

May 18, 2022
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Removing Java 8 JDK from Mac

So I installed the beta of JDK 8 a while ago to look at some of the examples. I thought for sure by ...

May 18, 2022
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How can I create a Java 8 LocalDate from a long Epoch time in Milliseconds?

I have an external API that returns me dates as longs, represented as milliseconds since the beginning of the Epoch. With the old ...

May 17, 2022
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