I would like to compare to streams, and check if they have 1 or more elements in common (finding 1 is sufficient to stop looking for more). I want to be able to apply this to Streams containing a custom-created class. For illustration, let’s say I have a class that looks like: And then I have two lovely…
Tag: java-stream
Java8 how to get list of objects based on the value [closed]
Closed. This question needs debugging details. It is not currently accepting answers. Edit the question to include desired behavior, a specific problem or error, and the shortest code necessary to reproduce the problem. This will help others answer the question. Closed 2 years ago. Improve this question Code …
Using wildcards in stream terminal operations
Hi2all. I’am reading a Java book and got to the chapter about StreamAPI classes. So, my questions is: why in terminal operation methods using lower bounded wildcards, like: Indeed, in fact, you can use unbounded wildcards like this: Is there any reason to use exactly lower- bounded wildcards? Answer You…
Java 8 convert for loop and summing of values to stream/lambda?
I have some String inputs that I am looping over that I am trying to convert to java 8 stream/lambdas but was having some issues. My boilerplate code looks like this: I was trying to do something like … but couldn’t get the summ’ing logic down. could anyone point me in the right direction? A…
Java – how to improve on this function (Java 8 streams)
I’ve coded a function that finds the unique characters in a string using Java 8 streams, based on an example here. To me, it’s pretty non-intuitive, maybe because I’m still learning streams. Is there any way to make this more readable? Here’s the code: Answer For calculating the actual…
How to pass ArrayList to JPA repository method from lambda expression?
There is entity class: How to pass callList to JPA repository.saveAll(callList) method ? Answer I think you should forget to call smth. from Steram. I do not say this is impossible, but it’s not recommended. List<Call> callList could be written into DB.
Create arraylist from list of maps for certain key value with java 8
I have an object with a list of maps. Each map looks like this: I am trying to create an array list of all the id’s in the maps. I can do this with a simple loop But how is this done in one line using java 8 streams? I have never used it with maps so I am lost.
Java 8 lambda expression or old way
Hello guys I’ve got question about Java 8 lambda expression. For example I want to delete following id from class. UserEntity userEntity = userEntityOptional.get(); for(Long permission_id : …
Combine list of list into map using stream
I’m trying to convert a pojo object that looks like into Map<String, List<String>>, such as: how can I accomplish this using stream? I preferably want to utilize stream into collect(), instead of using forEach() (which is basically a for-loop). Thanks in advance. EDIT: The pojo class looks s…
How to extract values from a list of class objects, remove the duplicates and sort alphabetically?
I have a class Tag in java and I am extracting descriptions from a list of Tag objects rawTags to a set (I need to remove duplicate values): but I also want to have the resulting set (or list of unique descriptions) alphabetically ordered. Is there a way how to use TreeSet directly with Collectors or what wou…