core java volume 2

language Features, object-oriented (encapsulation, inheritance, polymorphism), reflection, generics ... (2) Java Class Library: Core class library, such as Io/nio, network, Utils ... ; Security libraries, JDK, management, and massive third-party class libraries (3) Java Virtual machines: garbage collector, Runtime, dy

CDL) { This. i =i; This. CDL =CDL; } Public voidrun () {Try{TimeUnit.SECONDS.sleep (3); } Catch(interruptedexception e) {e.printstacktrace (); } System.out.println (I+ "is running"); Cdl.countdown (); } @Override PublicString toString () {return"I:" +i; } Public Static voidMain (string[] args)throwsinterruptedexception, executionexception {blockingqueue queue=NewArrayblockingqueue); Defines a blocking queue with a length of 2 Coun

0000,Which means 128 is 1000 0000 in the computer,The integer.tohexstring parameter is int, and if you do not 0xff, then when a byte is converted to int,Since int is 32 bits, and byte has only 8 bits, this will be the complement.For example, the decimal number of the complement 11111111 is 1 to int when converted to 11111111111111111111111111111111 many 1 ah, hehe!That is 0xFFFFFFFF but this number is wrong, and this complement will cause errors. and 0xFF and after the high 24 bits will be clea

when using Java commands, use the-xbootclasspath option or specify the Sun.boot.class.path system property value by using the-D option to specify that additional classes are loaded.The Genga carrier is not implemented in Java.2. Extension Classloader, known as the extension ClassLoader, is responsible for loading the class of jar packages of the JRE's extended d

Classes are loaded:　　Refers to reading the binary data of a class file into the runtime data area (the JVM is partitioned in memory)and creates a class object within the method area.Class Loader:Responsible for loading the compiled class file (bytecode file) into the JVM (Java Virtual machine).The class loader is mainly divided into the following types:1.Bootstrap class loader (boot class loader)Responsible for loading the

variable that is incremented to uniquely identify a rilrequest. This variable is used as token when it is sent, and tokens seen at the rild layer are the mserail.Event_end:[email protected]@[email protected]2) Send the steps: The first step: Generates a rilrequest that will generate m_serial (the requested token) and fill the request number, data, and result Message object into Rilrequest Step Two: Use Send to package rilrequest

external-operating system pointer), we can write a C + + function to find the form handle, and then return to the Java virtual machine, Let us also know within the virtual machine that a Java form is assigned a handle by the operating system. Jawt Java official has taken into account our needs, it provides an interface: JAWT. Includes a series of C

Java Multithreading Core technology comb (with source code) Java Multithreading Core Technology comb the source code written in front Java multithreaded objects and variables concurrent access between threads communication lock usage Timer single case mode and multithreadi

the implementation of the interface class to realize the replacement system.Definition of the interface:1. The naming conventions and classes of the interfaces are the same.Example: public interface interface Name {}2. Constants can be defined in the interface, and variables cannot be defined. The properties in the interface are automatically modified with public static final. The constants in the interface must specify the initial values when they a

Mastering Java Core Technology is the key to learning and mastering Java technology, with 17 points below to explain these Java core technologies. No more inheritance in 1.Java, but instead of multiple inheritance with interfaces

slower than just calling the method directly, so it is advisable to use the method object only when necessary, preferably with an interface and a lambda expression.In particular, we recommend that Java developers not use the callback function of the method object. Using an interface for callbacks can make your code execute faster and easier to maintain.7.8 Inherited design Tips1. Placing public operations and domains in a super class2. Do not use pro

Tags: Get select instance expression oca important localhost share databaseThe Java Tag Library is divided into the above several, generally used is the core and functions, the next will explain the various, and common usage. The General tag library is used with the El expression, so the use of the El expression is also studied before learning the tag library. Expand after import The corresponding tag libr

and implementation of interface Autowirecapablebeanfactory Configurablelistablebeanfactory:beanfactory configuration checklist, specifying the green type and interface Defaultlistablebeanfactory: Combines all of the above functional groups to be processed after the bean is registered 2.XmlBeanDefinitionReader From this diagram we can see how this cl

This article is based on the 12th chapter of the Java Core Reel, and the more detailed information is in the Java core Reel.1. Generic types can only be reference types and cannot use basic data types. 2. Type variable meaning　　 E: set K: keyword V: value T: any type 3.

No more inheritance in 1.Java, instead of multiple inheritance with interfaces2. When running a compiled program, the Java interpreter always executes from the code in the main method of the specified class, so there must be a main function in the execution code.3.Java is a typical strongly typed language, that is, you must declare the type of the variable, there

Core technology in Java EE 13 (1)extensible Markup Language (XML)XML is a language that can be used to define other markup languages (2) JavaServer Pages (JSPs)used to create dynamic Web pages (3)Java servlets Most of the features offered are similar to JSPs, but are implemented in different ways (4)

Java object-oriented-abstract classes and interfacesUse of the 1.Java final keywordPackage edu.tongji.fni;/*final keyword * 1, the final keyword in Java is called the end device, which means the final meaning * 2, Final can declare classes, methods, properties: * Classes that use Final declaration cannot be inherited *

Java cache Ehcache-core class and method introduction and use instance, javaehcache-Core classes and methods in Ehcache The EhCache contains a CacheManager type, which is used to manage the cache. The Cache stores the Element object. The Element must be a key-value pair. The Cache is physically implemented in the memory or disk. The logical representation of the

1. PrefaceRecently, I've seen several interesting questions about the Java Core class string. The string class is how to implement its immutable attributes, and the benefits of being designed to be immutable. Why is it not recommended to use the + sign to form a new string, it is recommended to use StringBuilder or StringBuffer. Flip through some of the online blogs and StackOverflow, comb

Transferred from: https://www.oschina.net/question/3756233_2277445Multi-line threads for other Java knowledge points, there is a certain threshold for learning, and it is more difficult to understand. In peacetime work if improper use will appear data confusion, inefficient execution (as a single-threaded to run) or deadlock program hangs and so on, so mastering the understanding of multithreading is critical.From the beginning of the basic concept to