May 13, 2009 · In Java 8. To create a non-empty list of fixed size (operations like add, remove, etc., are not supported): List<Integer> list = Arrays.asList(1, 2); // but, list.set(...) is supported To create a non-empty mutable list: List<Integer> list = new ArrayList<>(Arrays.asList(3, 4)); In Java 9. Using a new List.of(...) static factory methods:

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.

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.

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.

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));

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; ...

And a List's Iterator returns items in sequential order. For the Consumer, this code passes in a method reference (Java 8 feature) to the pre-Java 8 method List.addAll to add the inner list elements sequentially.

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();

As all classes implementation extends implicit or explicit from java.lang.Object class, this list can hold any object, including instances of Employee, Integer, String etc. When you retrieve an element from this list, you will be retrieving an Object and no longer an Employee , meaning you need to perform a explicit cast in this case as follows: