lots of exercises in java... from https://github.com/exercism/java
Stuart Kent 2d1da4c399 perfect-numbers: add to track 9 gadus atpakaļ
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example/java perfect-numbers: add to track 9 gadus atpakaļ
main/java perfect-numbers: add to track 9 gadus atpakaļ
test/java perfect-numbers: add to track 9 gadus atpakaļ