Which four methods delete all null values in List

In this issue, the editor will bring you about the four ways to delete all the null values in List. The article is rich in content and analyzes and narrates it from a professional point of view. I hope you can get something after reading this article.

1 introduction

The evil null has been torturing programmers for a long time, and it has also brought a lot of hard-to-find but costly NullPointerException. We need to avoid it as much as possible, and a simple way is to strangle it in the cradle before it enters the next round of processing.

This paper mainly introduces four kinds of methods, namely, the method of List interface, Stream, Guava and Apache Commons Collections to delete the null value in a List.

2 four kinds of methods 2.1The methods included in List

There are many remove methods available for List, and the following three can meet our needs:

List.remove (Object o): delete an element and return true; if successful. Note that it only deletes one element.

List.removeAll (Collection c): delete all cases where set c exists, note that the input parameter is not an element

List.removeIf (Predicate