Oct 1, 2008 · If You Can't... For an Immutable List. Use the JDK's Arrays class and its asList() factory method, wrapped with a Collections.unmodifiableList():

Jun 17, 2009 · But preferably, just use the Stream without collecting it to a List. If you specifically need a java.util.ArrayList * If you want to both prepopulate an ArrayList and add to it afterwards, use. List<String> strings = new ArrayList<>(List.of("foo", "bar")); or in Java 8 or earlier: List<String> strings = new ArrayList<>(asList("foo", "bar")); or ...

List<String> x = new ArrayList<>(Arrays.asList("xyz", "abc")); If you don't want to add new elements to the list later, you can also use (Arrays.asList returns a fixed-size list): List<String> x = Arrays.asList("xyz", "abc"); Note: you can also use a static import if you like, then it looks like this: import static java.util.Arrays.asList; ...

Jun 6, 2013 · 1st of all, when you declare a variable in java, you should declare it using Interfaces even if you specify the implementation when instantiating it. ArrayList<ArrayList<String>> listOfLists = new ArrayList<ArrayList<String>>(); should be written. List<List<String>> listOfLists = new ArrayList<List<String>>(size);

May 13, 2009 · Ints.asList does not create an immutable list, but a fixed-size list backed by given array of ints (i.e. it supports List.set(int, Object)). Second example of "Immutable List of Characters" isn't immutable either (I'd remove that line). –

Oct 20, 2010 · If you want to allow a user to add a bunch of new MyObjects to the list, you can do it with a for loop: Let's say I'm creating an ArrayList of Rectangle objects, and each Rectangle has two parameters- length and width.

oh okay, i think i understand. well, the only reason i had that method was because i didn't know where that "magic one liner" was. hence, that's why i asked this stackoverflow question in the first place. if i already knew that one line Arrays.asList(s), then why would i ask my question here on stackoverflow? i was surprised to find that this convenience method is …

May 11, 2021 · You can create Array of ArrayList. List<Integer>[] outer = new List[number]; for (int i = 0; i < number; i++) { outer[i] = new ArrayList<>(); } This will be helpful in scenarios like this. You know the size of the outer one. But the size of inner ones varies. Here you can create an array of fixed length which contains size-varying Array lists.

Aug 2, 2013 · Is there a way to create a list of primitive int or any primitives in java. No you can't. You can only create List of reference types, like Integer, String, or your custom type. It seems I can do List myList = new ArrayList(); and add "int" into this list. When you add int to this list, it is automatically boxed to Integer wrapper type.

Jan 17, 2012 · I faced with the similar issue, and just knowing the arrayList is a resizable-array implementation of the List interface, I also expect you can add element to any point, but at least have the option to define the initial size. Anyway, you can create an …