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 ...

Jun 29, 2011 · {{Double-brace initialization}} is known to create classpath clutter and slow down execution. It also requires one line of code per element. Java 9: the static factory method List.ofreturns a structurally immutable list. Moreover, List.of is value-based, and therefore its contract does not guarantee that it will return a new object each time.

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.

If you do plan on rolling your own framework, I'd also suggest not using List<List<String>> as your implementation - you'd probably be better off implementing CSVDocument and CSVRow classes (that may internally uses a List<CSVRow> or List<String> respectively), though for users, only expose an immutable List or an array.

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; ...

Oct 1, 2008 · In Java 9, you can use List.of static factory method in order to create a List literal. Something like the following: Something like the following: List<Element> elements = List.of(new Element(1), new Element(2), new Element(3));

Imagine that I have a list of certain objects: List&lt;Student&gt; And I need to generate another list including the ids of Students in the above list: List&lt;Integer&gt; Avoiding using a loop,...

Jan 17, 2012 · the size is the number of elements in the list; the capacity is how many elements the list can potentially accommodate without reallocating its internal structures. When you call new ArrayList<Integer>(10), you are setting the list's initial capacity, not its size. In other words, when constructed in this manner, the array list starts its life ...

List<ViewValue> source = newArrayList(new ViewValue(1), new ViewValue(2), new ViewValue(2)); We could make transformation with List class from Javaslang library (on the long run the collect is not convenient): List<Long> result = io.vavr.collection.List.ofAll(source).map(ViewValue::getId).toJavaList();

Nov 1, 2010 · There are some differences between the way you're creating a linked list and the way the Java collections API does it. The Collections API is trying to adhere to a more complicated interface. The Collections API linked list is also a doubly linked list, while you're building a singly linked list.