Lists in Java

The resizable workhorse collection.

import java.util.ArrayList;
import java.util.List;

// List.of is fixed; wrapping it in ArrayList makes it editable
var todo = new ArrayList<>(List.of("write", "compile", "ship"));
todo.add("celebrate");
todo.add(0, "plan");
todo.remove("compile");

System.out.println(todo.size() + " items");
System.out.println(todo.contains("ship"));
System.out.println(todo.indexOf("ship"));
System.out.println(String.join(" -> ", todo));

How it works

1. List.of is fixed; wrapping in ArrayList makes it editable.
2. add, add(0, ...) and remove grow and shrink in place.
3. contains and indexOf search by value.

Keywords and builtins used here

• new
• var

The run, in numbers

Lines

13

Characters to type

425

Tokens

129

Three-star pace

95 tpm

At the three-star pace of 95 tokens a minute, this run takes about 81 seconds.

Type this snippet

Step 2 of 4 in Collections, step 12 of 29 in Language basics.

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Lists in other languages

• C#
• R