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Java5: Generics:After referencing generics, it allows you to specify the type of elements in a collection, eliminates mandatory type conversion, and has the advantage of type checking at compile time. As parameters and return values, Generic is the cornerstone of vararg, annotation, enumeration, collection. A. Type Safety When y ...

Class Eny2 Keywords: Inheritance; Object class; Polymorphism; inherit Through the extends keyword; Subclasses can inherit all non-private ly owned properties and methods from their parent class as members. When a subclass inherits a parent class, it should first satisfy that the parent class is accessible, for example, when the subc ...

As for groovy support scripts and classes, the previous section will briefly describe the relationship between scripts and classes. This section mainly introduces the related knowledge of classes in groovy, that is, object-oriented knowledge. 1. Types 1.1 Primitive Type groovy supports the same raw data types as java, boolean, char, short, int, ...

DK 1.5 introduces a new type, enumeration. Although it is a "small" function in Java, it brings "big" convenience to my development. Usage 1: Constants Before JDK 1.5, we defined constants as: publicstaticfianl.... Now, with enumeration, you can group related constants into an enumeration type, and enumeration provid ...

Synchronization Control of Collections Collections. Synchronized Collection Sets Several synchronized Xxx methods are provided in the Collections class: This method returns the synchronization object corresponding to the specified collection object to solve the thread security problem when multithreading accesses the collection concurrently. ...

The license contains registration information, a string of key-value pairs.   Symmetric encryption: DES, AES, encryption and decryption all use a secret key, fast speed Asymmetric Confidentiality RSA can encrypt and decrypt public key with private key, or decrypt public key and private key with slow speed. Be careful:RSA encrypts plaintext with ...

Java There are three main ways to realize multithreading: inheriting Thread class, implementing Runnable interface, using Executor Service, Callable and Future to realize multithreading with returned results. The first two methods of thread execution have no return value, only the last one is with return value. 1. Implementing multithr ...

FutureTask is an asynchronous task executor that supports cancellation behavior. This class implements the method of Future interface.Such as: Cancel Task Execution Query whether the task is completed Get the result of task execution ("get" task must be executed to get the result, otherwise it will block until the task is complete ...

Page Helper is used to paginate with mybatis and Page Interceptor is used to understand the interceptor of mybatis. Mybatis version is 3.4.6, and Mybatis Helper version is 5.1.3. 1,PageInterceptor Start with the previous code, List-1 as follows:     List-1 @Test public void testPage() { PageHelper.startPage(2, 3); List<Person ...

PinPoint installation deployment and the pit I encountered PinPoint collector deploys, configures Tomcat and Dubbo services PinPoint Use Tutorial Some pits PinPoint trampled on HBase and PrinPoint are deployed on different servers PinPoint implements mail alert After installing pinpoint, click the settings button in the upper right corne ...