What is the shortest way to initialize List of strings in java?

Question

I am searching for the shortest way (in code) to initialize list of strings and array of strings, i.e. list/array containing \"s1\", \"s2\", \"s3\" string elements.

Answer 1

Java 9+

Java 9 introduces a convenience method List.of used as follows:

List l = List.of("s1", "s2", "s3");

Java 8 and older

Here are a few alternatives:

// Short, but the resulting list is fixed size.
List list1 = Arrays.asList("s1", "s2", "s3");

// Similar to above, but the resulting list can grow.
List list2 = new ArrayList<>(Arrays.asList("s1", "s2", "s3"));

// Using initialization block. Useful if you need to "compute" the strings.
List list3 = new ArrayList() {{
    add("s1");
    add("s2");
    add("s3");
}};

When it comes to arrays, you could initialize it at the point of declaration like this:

String[] arr = { "s1", "s2", "s3" };

If you need to reinitialize it or create it without storing it in a variable, you do

new String[] { "s1", "s2", "s3" }

If the string constants are may though, it would look like

String[] arr = { "s1", "s2", "s3", "s4", "s5", "s6", "s7", "s8", "s9", "s10",
                 "s11", "s12", "s13" };

In these cases I usually prefer writing

String[] arr = "s1,s2,s3,s4,s5,s6,s7,s8,s9,s10,s11,s12,s13".split(",");