I have two list of different Objects. I want to remove the list of School objects from List of World objects based on schoolName and location. I cannot use equals and hashCode methods on those two fields as it is creating some other problem. Please help me how it can be done using streams. Answer You can use …
Tag: java-stream
Combine two Stream into one Flux
How can I combine two streams Stream<String> into Flux? What I understand is that I might need to use Flux create method to create this but I am not really sure about it: Please help. Answer Concat the Streams into one and then invoke Flux#fromStream: Another way of doing this would be to create a Flux …
Convert 3 arrays into 1 object array using Streams
Lets say I have the following three arrays: int r[] = {255,255,255}; int g[] = {0,0,0}; int b[] = {255,255,255}; All arrays will have same length. I want to convert them into an array of objects of …
parallelStream() java 1.8 vs 11
Consider the following code: When it is compiled and run with java 11, it returns the following: But with java 1.8, it returns different result: Why results are different? Answer Both results are consistent with the Java Memory Model. One possible ordering in which execution occurs is: but, because you don…
Calculate the percentage of value using Collection framework
I have List of TrainingRequest where each and every element has List of Feedback. I need to get all given result of Q1,Q2 and calculate percentage of each value. To flat all the feedback To calculate each value of Q1 and Q2, I’m grouping it and getting the count. I need to get the percentage of each Q1,…
How to convert short[] into List in Java with streams?
I figured I could extrapolate from this question but I can’t I can of course do But I’m wondering how to do it with streams. doesn’t work for example but yields The method stream(T[]) in the type Arrays is not applicable for the arguments (short[]) Answer Why not
Creating a map from nested lists
Suppose there are 3 classes: Suppose there is a List of Level1 objects called initial state I want to create a map from initialList where: I am able to achieve this using for loops, but I want to achieve this in a more elegant way using Java 8 features (streams and the functions). I tried using Collectors.toM…
Call custom static functions from filter and map in Java 8 – stream
I want to call method name nameStartingWithPrefix() which is inside filter and its definition will be in Filter class. All ArrayList describes in main(), but the list is not passed as in an argument, how can I call in List of names inside Filter.nameStartingWithPrefix(). Syntax is given like: names is name of…
Direct conversion from Collection to LongStream
I have a Collection<Long> (obtained from a Map<UUID, Long>’s values() method) and I would like to convert it into a LongStream. The simplest way I can think of is: However it strikes me that there should be a simpler way to obtain primitive streams from Collections of boxed equivalents. I ch…
Convert a list of integers into a comma-separated string
I was trying to convert a list of Integers into a string of comma-separated integers. Collectors.joining(CharSequence delimiter) – Returns a Collector that concatenates the input elements, separated by the specified delimiter, in encounter order. I am getting an error in line number 8: The method collec…