Divide the List into arbitrary numbers

Conclusion

Use org.apache.commons.collections4.ListUtils # partition ().

Javadoc https://commons.apache.org/proper/commons-collections/apidocs/org/apache/commons/collections4/ListUtils.html#partition-java.util.List-int-

Maven https://mvnrepository.com/artifact/org.apache.commons/commons-collections4/4.4

<!-- https://mvnrepository.com/artifact/org.apache.commons/commons-collections4 -->
<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-collections4</artifactId>
    <version>4.4</version>
</dependency>

Usage example (1)

Specify the maximum number of elements per one

List<String> list0 = Arrays.asList("aaa", "bbb", "ccc", "ddd", "eee", "fff", "ggg");
List<List<String>> lists = ListUtils.partition(list0, 3);
for (List<String> list : lists) {
	System.err.println(list);
}

[aaa, bbb, ccc]
[ddd, eee, fff]
[ggg]

Usage example (2)

Specify how many you want to divide

List<String> list0 = Arrays.asList("aaa", "bbb", "ccc", "ddd", "eee", "fff", "ggg");
List<List<String>> lists = ListUtils.partition(list0, list0.size() / 2 + 1);
for (List<String> ll : lists) {
	System.err.println(ll);
}

[aaa, bbb, ccc, ddd]
[eee, fff, ggg]

Background

I made a similar method by myself and completed it, but I realized that "This is in Commons !?" and came to the discovery orz.

that's all.