Programmer Think

1, What is a simple factory 1) Simple factory mode belongs to the creation mode, which is a kind of factory mode. The simple factory pattern is that a factory object determines which product class instance to create. Simple factory model is the simplest and most practical model in the factory model family 2) Simple factory pattern: defines a ...

Java file streaming and I/O file concept A file is where data is stored.File stream: files are operated in the form of stream in the program.Stream: the path of data between the data source (file) and the program (memory)Input stream: the path of data from data source (file) to program (memory)Output stream: the path of data from program (me ...

1. Reliable messaging for ultimate consistency We have studied the CAP theory before and know that we generally guarantee P and A, abandon C and ensure the final consistency. Distributed transaction The core of using message queue to achieve final consistency is to split distributed transactions into multiple local transactions, and then coord ...

catalogue 1, Multiple choice questions 2, Programming problem 1. Sort subsequence 2. Inverted string 1, Multiple choice questions 1. Resolution: Both parent class and new subclass objects are allowed 2. Resolution: You can see from the source code of String method tolower case The return value of this method means that if the ...

catalogue Creation of one-dimensional array Initialization of one-dimensional array Use of one-dimensional array Storage of one-dimensional array in memory Creation of two-dimensional array Initialization of two-dimensional array Use of two-dimensional arrays Storage of two-dimensional array in memory Array out of bounds Array as fu ...

preface When it comes to robbing red envelopes, you must be very familiar with it, especially wechat robbing red envelopes, which we contact almost every day. Although the amount of red envelopes we grab each time varies from big to small, we are deeply immersed in the happiness of grabbing red envelopes 😄. But then again, I wonder if you gu ...

Multithreading 1.1 basic concepts: program, process and thread Program: a set of instructions written in a certain language to complete a specific task. It refers to a piece of static code, static objectProcess: it is an execution process of a program or a running program. It is a dynamic process: it has its own process of emergence, existenc ...

1. Why do you need to use design patterns? Using design patterns to reconstruct the whole code can improve the reusability and scalability of the code and reduce code redundancy. 2. Talk about the six principles of design mode? Open Close Principle: the Open Close Principle is open to extensions and closed to modifications. When the prog ...

Blocking queue Blocking queues are often used in producer consumer scenarios. In java8, JUC provides seven blocking queues. Class nameeffectArrayBlockingQueueThe bounded blocking queue implemented by the array sorts the elements according to the first in first out (FIFO) principle.LinkedBlockingQueueA bounded blocking queue implemented by a l ...

ArrayList underlying source code conclusion ArrayList maintains an array of object type elementdata (transient Object[] elementData;)When creating an ArrayList object, if a parameterless constructor is used, the initial elementData capacity is 0. If it is added for the first time, the expanded elementData is 10. If it needs to be expanded aga ...