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This article mainly shows you "how to initialize ArrayList in Java", the content is simple and easy to understand, clear organization, I hope to help you solve doubts, let Xiaobian lead you to study and learn "how to initialize ArrayList in Java" this article bar.

1 Cause

In actual business development, we often encounter situations where we need to create an array temporarily.

2 solutions

To conclude, there are four initialization methods:

double bracket method

Arrays.asList

stream

Lists

2.1 List test = new ArrayList(){{ add(1); add(2);}};2.2 Arrays.asListList test = Arrays.asList(1, 2, 3);

The array generated in this way cannot be modified. To modify it, you can use the following method:

List test = new ArrayList(Arrays.asList(1, 2, 3));2.3 streamList test = Stream.of(1, 2, 3).collect(Collectors.toList());2.4 Lists

Java 9 can be used later.

List test = Lists.newArrayList(1, 2, 3);3 Summary

Finally, I ran a race for the first three methods, which took the following time (FYI):

Arrays.asList(0) > Double parenthesis (9) > stream(36)

The above is "How to initialize ArrayList in Java" all the content of this article, thank you for reading! I believe that everyone has a certain understanding, hope to share the content to help everyone, if you still want to learn more knowledge, welcome to pay attention to the industry information channel!

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