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Tag: list

extract list inside a list as a single list

I’ve a two POJOs, Sample code below Controller class This returns me a list of the list: but what I want is a single list like How can I do that with Java 8 streams? I’ve tried flatMap also, but that doesn’t go well with the Object datatype of entries. Answer Consider a List<String> as a field entries in the

How to get Cartesian product from multiple lists?

Say I have several List<T>s, I will put them into another list or other collections, so I don’t know how many list<T> I have until I call List<List<T>>.size() Take below List<Integer> as an example: How can I get the result of list1*list2*list3*…listn as a Cartesian product? For example: should be: Answer You can use recursion to achieve it, your base

Jackson read json in generic List

I’m using Jackson in order to read json messages. One of the values that I’ trying to parse is a List and another value contains the type of the data in the list. This is the structure i ‘ve created in java. Through Class.forName(); I can get the class which represents the data in the list. The question is how