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Tag: java-8

Converting string to Map in java 8

Can someone please guide me on how to achieve the below using Java 8. I don’t know how to get that counter as the key Answer You can use IntStream to get this thing done. Use the integer value as the key, and the relevant value in the string array at that index as the value of the map. Another

handle duplicate key in Collectors.toMap() function

I am creating a map which its (key,value) will be (name, address) in my Person object: In the duplicate key situation, I would like to skip to add the second address to the map and would like to log the name also. Skipping the duplicate address I can do already using mergeFunction, but in oder to log the name I

LocalTime() difference between two times

I have a flight itinerary program where I need to get difference between departure and arrival time. I get these specified times as String from the data. Here is my problem: Output: The first time returns the difference between 11:39 and 14:35 just fine. But the second difference is only 5 hours while it should be 19 hours. How can

How do I use MapElements and KV in together in Apache Beam?

I wanted to do something like: Where User is a custom datatype with Arvo coder and a constructor that takes a string into account. However, I get the following error: Cannot select from parameterized type I tried to change it to TypeDescriptor.of(KV.class) instead, but then I get: Incompatible types; Required PCollection> but ‘apply’ was inferred to OutputT: no instance(s) of

Java 8: How to convert String to Map?

I have a Map: I converted it to a String: How to convert utilMapString to Map in Java8? Who can help me with? Answer Split the string by , to get individual map entries. Then split them by = to get the key and the value. Note: As pointed out by Andreas@ in the comments, this is not a reliable

Should I use shared mutable variable update in Java 8 Streams

Just iterating below list & adding into another shared mutable list via java 8 streams. What is the difference between above three iteration & which one we need to use. Are there any considerations? Answer Functionally speaking,for the simple cases they are almost the same, but generally speaking, there are some hidden differences: Lets start by quoting from Javadoc of

How to implement the Elvis operator in Java 8?

I have the classic “Elvis operator” case, where I’m calling methods that each may return null and chaining them together: In Java 8, the most faithful implementation I’ve found is something like this: I wish that Java’s Optional had something akin to the elvis operator: So that I wouldn’t have to wrap each return value: Is there a more efficient

Void is not a functional interface

I am trying to subscribe observable like : It’s working fine but if I use method reference compiler gives error “void is not a functional iterface” Any one can explain little bit deep? As per me subscriber accept consumer functional interface, which doesn’t return anything but we can print stream data like : Answer Your method reference syntax is wrong.

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