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Tig - a great partner of git

Tig is an ncurses-based text-mode interface for git. It functions mainly as a Git repository browser, but can also assist in staging changes for commit at chunk level and act as a pager for output from various Git commands.

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Design Pattern - Factory Pattern

I am working on some simple AWS lambda functions now. To get the better performance, I decide to get rid of Spring framework in most of them as they are simple and straightforward. But without having a mature framework, it should be more carefully as I need to implement several methodologies by myself instead of using things provided by the framework. So, I decide to refresh my knowledge of the basics, like common design patterns in object oriented programming. I am going to talk about a few design patterns by summarizing the resources I found, putting my own thoughts and including some Java code examples in the next few posts.

Today, I am going to start our journey with Factory Pattern.

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Why the size of Hashmap is power of 2 in Java

As we know, the Hashmap is implemented by a bucket of linked lists or red-black trees. However, when we look into the source code of Hashmap in Java 8, there are interesting comments on attributes related to the size of bucket, e.g. DEFAULT_INITIAL_CAPACITY and MAXIMUM_CAPACITY. It is said these values MUST be a power of two.

So, what’s the reason that the bucket size of a Hashmap has to be a number, which is power of two?

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