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This article will mainly talk about JDK version 1.8 Concurrent HashMap, its internal structure and many hash optimization algorithms are the same as JDK version 1.8 HashMap, so before reading this article, we must first understand HashMap, for reference. HashMap correlation In addition, there are also red and black trees in Concurrent HashMap, ...

premise javax.crypto.Cipher, translated as a password, is actually better known as a crypto. Cipher is the core of JCA(Java Cryptographic Extension), which provides encryption and decryption functions based on a variety of encryption and decryption algorithms. Before we know Cipher, we always need to copy code everywhere when we complete some m ...

1. Understanding ThreadLocal ThreadLocal, also known as thread local variables or thread local storage. ThreadLocal creates a copy of the variable in each thread, so each thread can access its own internal copy variable. Let's start with an example: class ConnectionManager { private static Connection connect = null; ...

As an aside, many people call the NIO provided by JDK 1.4 asynchronous non-blocking I/O; in fact, it is not. Strictly speaking, it can only be called non-blocking I/O. In NIO 2.0 provided by JDK 1.7, an asynchronous socket channel Channel is added, which is the real asynchronous non-blocking I/O. The following table com ...

In Java, generics and reflection are two important concepts that we can almost always use. And when it comes to Type, if anyone is unfamiliar with it, we should all understand that it is a direct implementation class, Class. Type is the common parent interface of all types in the Java language. This article is mainly about t ...