Java

Theoretical learning of getting started with JavaIn the course of JAVA2 using the tutorial, it is divided into the following modules to explain The status of Java Features of Java Installing the JDK (Java develepement Kit) Development

Decimal turns into 16 binary:integer.tohexstring (int i)Decimal into octalinteger.tooctalstring (int i)Decimal turns into binaryinteger.tobinarystring (int i)Hex turns into decimalInteger.valueof ("FFFF", +). ToString ()Octal into

20165324 "Java program design" the first week to summarize the learning contents of teaching Materials Chapter I: Getting Started with JavaKey one, write Java programs The first step is to write the source file (Note: Java is strictly

1. ArrayList's sublistThe result can not be strongly turned into ArrayList, otherwise throw classcastexception exception, because Sublist returned is ArrayList's inner class sublist, not ArrayList, but a view of ArrayList. Example Public class

I don't understand, do you study? If you remember.public static long round (double a) {Long longbits = Double.doubletorawlongbits (a); Long Biasedexp = (Longbits & doubleconsts.exp_bit_mask) >> (doubleconsts.significand_width-1); Long

First, futureThe future and callable are basically in pairs, callable is responsible for producing results, and the future is responsible for obtaining results. 1. The callable interface is similar to runnable, except that runnable has no return

1.Maven Package an executable jar: Build> Plugins> plugin> groupId>Org.apache.maven.pluginsgroupId> Artifactid>Maven-compiler-pluginArtifactid> version>3.7.0version>

The inner classes in Java are divided into four: member Inner class Static Inner class Local inner class Anonymous inner class 1. member Inner class:Defined inside another class (outer Class), and with member methods and

Java historyAccording to the usual parlance, the hoot of Java astonished can be traced back to the year 1991. At the time, Sun set up a project called Green, which is dedicated to communication and collaboration between digital appliances. James

PackageCom.cvicse.ump.timer.service;Importjava.util.Date;ImportJava.util.Timer;Importcom.cvicse.ump.timer.task.TimTaskTest;/*** Timed Task Manager *@authorDyh **/ Public classTimermanager {/*** Single case mode*/ Private StaticTimermanager

1. Bitwise XOR or operation (^)The arithmetic rules are: two numbers are converted to binary, then compared from high, if the same is 0, not the same is 1.For example: 8^11.8 to binary is 1000,11 to binary is 1011. The comparison from the high level

Pessimistic lock (Pessimistic Lock), as the name implies, is very pessimistic, every time to take the data when they think others will change, so every time when the data are locked, so that other people want to take this data will block until it

plane-oriented programmingAOP thought: Horizontal duplication of code, vertical extractionAOP embodies--filterAOP embodied-interceptorsAOP embodies--dynamic agentImplementing AOP Ideas in springPrinciple: Spring can generate proxy objects for

Basic Basics Object-oriented features Final, finally, finalize the difference What is the difference between int and Integer The difference between overloading and overriding What is the difference between an abstract class

What is a stream?Flow in Java refers to a buffer that flows in a calculationClassification of streamsThe main differences between character streams and byte streams are: When a byte stream is read, it returns a byte when it is read, and the

To process the date format, run the main function: PackageTestutil;ImportJava.text.SimpleDateFormat;ImportJava.util.Calendar;Importjava.util.Date;/*** Created by Wangpeng on 2018/2/26.*/ Public classDateFormat { Public Static voidMain (string[] args)

You first need to introduce the following jar packagesIf you use MAVEN, you need to add two dependencies Dependencies> Dependency> groupId>Org.apache.poigroupId> Artifactid>PoiArtifactid> version>3.15version>

Java implements random and non-repeated numbers. Generally, developers with some development experience can achieve this function, but it is only a matter of efficiency. In general, when we are faced with such a problem, we will always think of it

Java string Term Frequency Statistics instance code, java Term Frequency Copy codeThe Code is as follows:Package com. gpdi. action;Import java. util. ArrayList;Import java. util. Collections;Import java. util. HashMap;Import java. util. List;Import

Java 9 distinguishes between opens and exports, and java9opensexports Collation This article mainly studies some precautions for migrating data to Java 9. Migration type The code is not modularized. First, it is migrated to jdk9 to make good use