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ArrayList has three initialization methods public ArrayList() public ArrayList(int initialCapacity) public ArrayList(Collection<? extends E> c) The first parametric construction method /** * Constructs an empty list with an initial capacity of ten. */ public ArrayList() { ...

DockerFile file Note: Mode 1 is the Docker File file that I used when I built the Docker image in SpringBook, which can be modified by myself. 1. Building a SpringBook Project Mirror Based on the Existing JDK Mirror #Setting up JDK image FROM openjdk:8-jdk-slim VOLUME /tmp MAINTAINER sunhui #ti ...

Original Link: http://www.cnblogs.com/cgfree/p/5397890.html This tutorial describes how to install and CentOS Configure the latest on servers 7, 6.5, and 6.4 Oracle JavaJDK for.Although these steps should also apply to other RPM-based d ...

1. Definition: An instance of which product class is created is determined by a factory object. 2. Types: Creative, but not GOF23 design pattern 3. Use scenarios: The factory class is responsible for creating fewer objects. The client (application layer) only knows the parameters that are passed into the factory class, and does not care about h ...

Prototype pattern - A prototype instance specifies the type of object created and creates new objects by copying these prototypes. The caller does not need to know any creation details and does not call the constructor! It belongs to the creation mode. It does not create other objects by new, but by using existing objects in memory as template ...

Method Rewriting (Supplementary) In case of rewriting: Inheritance Method Name Same The list of parameters should be identical (order, number, type) When the return value type is a reference type, the return value type of the subclass is exactly the same when it is less than or equal to the basic typ ...

Map collection 1.1. Overview In real life, we often see such a set: IP address and host name, ID number and individual, system user name and system user object, etc. This one-to-one correspondence is called mapping. Java provides a special collection class to store the object of this object relatio ...

AOP AOP provides a new way to think about program structure to supplement OOP. The key of module in OOP is class, while the key of module in AOP is aspect. Aspects support modularization across multiple types and objects, such as transaction management. AOP concept Aspect -- The process of performing notification operations at pointcuts (class ...

Object class Object is the parent of all classes, that is, all classes can be received with Object. Except for Object classes, all classes have inheritance relationships.Obtaining object information Getting object information, using the toString method package obj.exe.bit; class Person{ private String ...

Summary The following is based on JDK 1.8 data structure HashMap is actually an "array + linked list" data structure. In the put operation, the subscript of the array is found by the internal definition algorithm, and the data is directly put into the element of the array. If the element o ...