core java volume 1

can be executed independently in a process.A process can contain multiple threads, and a thread in the same process shares the resources owned by the process, such as memory space and file handles.Therefore, the process is a thread container, we use multithreading to carry out the concurrent design of the program, because the cost of scheduling is much smaller.2. Thread Life cycleThreads in Java have the following states:

I. Overview of new Java IOThe input and output streams in the Javaio are handled through byte movement, and the stream-oriented input-output system can handle only one byte at a time, so it is inefficient and the traditional input-output stream is blocked, meaning that when the data is unreadable, the current thread is blocked until it is read to a valid data to continue running.After java1.4, a series of improved input and output classes and methods

As a business developer, there are few technologies that can be used at work. Although usually always say what, multi-threading, concurrency, injection, Attack! But in practical work, these things are not necessarily used. Because the framework we used has already done that.For example, web development, there are a lot of requests coming in, supposedly, we should consider concurrency problems. But in fact, Spring receives the request, after assigning to the controller, it is already thread-safe,

First of all, the concurrent class library should be a very important class library in java. When building some Synchronous Code, containers, and concurrency, you can find ready-made and usable classes in this class library... The most core type in this class library is the AbstractQueuedSynchronizer type. You can implement your own synchronization tools based on it. For example, the ReentrantLock type is a

. String---> Byte streamCombines the functions of both bufferedwriter/outputstreamwriter2. can automatically refreshNew PrintWriter (os,true);UDP User Data Message Protocol-------------------------------------------1) Consider the efficiency of data transmission, reliability is not guaranteed2) Not necessarily a one-to-many communication, such as broadcasting3) non-connected, unreliable transmission modeDatagramsocket responsible for sending and recei

Memory Stream (Array stream):The data is temporarily present in the array and will be retrieved from the array later.1. Byte memory stream: Bytearrayinputstream/bytearrayoutputstream2. Character Memory stream: Chararrayinputstream/chararrayoutputstream3. String stream: Stringreader/stringwriter (storing data in an array)BYTE memory stream: Public classBytearraydemo { Public Static voidMain (java.lang.string[] args)throwsException {//byte array output

, Len)); - } -Bin.close ();}BufferedWriter and BufferedReader Public Static voidMain (string[] args)throwsIOException {//OutputBufferedWriter out =NewBufferedWriter (NewFileWriter ("Stream.txt",true)); Out.write ("Hoe wo Day Copse"); Out.newline ();//line BreakOut.write ("Sweat wo xia tu"); Out.close (); //inputBufferedReader in =NewBufferedReader (NewFileReader ("Stream.txt")); Char[] buffer =New Char[1024]; intLen =-1; while(len = in

PublicFirsrtactor () { - This. Init (); - } - Private voidinit () { +Texture=NewTexture ("Badlogic.jpg"); - } + @Override A Public voidDraw (Batch batch,floatParentalpha) { atBatch.draw (texture,0,0); - } - -}1 PackageCom.mygdx.useactor;2 3 ImportCom.badlogic.gdx.ApplicationAdapter;4 ImportCom.badlogic.gdx.Gdx;5 Importcom.badlogic.gdx.graphics.GL20;6 ImportCom.badlogic.gdx.graphics.g2d.SpriteBatch;7 /**8 * Gam

-generated Catch blockE.printstacktrace (); } }}4. Use Ruturn to stop the thread Public classMyThreadextendsThread {@Override Public voidrun () { while(true) { if( This. isinterrupted ()) {System.out.println ("Stop it!"); return; } System.out.println ("Timer=" +System.currenttimemillis ()); } } Public Static voidMain (string[] args)throwsinterruptedexception {MyThread T=NewMyThread (); T.start (); Thread.Sleep (2000); T.interrupt (); }}Results:Two(

1. String strings1) Description of String typeThe string class is final decorated, and the string object is an immutable object, and once created in memory, the content cannot be changed, and a new object is created to change the contents of the string.A string object is created with static and dynamic points.String str1 = "Dadsadad";String str2 = new String ("Dasdasdadad");2) string constant poolThe JVM has a restriction on strings, so that strings a

Well known in. NET, the key generated by the RSA class is in XML format, while other languages such as Java generally use the PKCS8 format key, JavaScript generally uses the PKCS1 format. We in the development process is likely to encounter the need to interface with other languages developed API, if we encounter RSA encryption and decryption, we must ensure that key is the same, in order to ensure the correct processing of data, we definitely need to

asvalues = Size.values();Returns an array containing the element size.small,size.medium,,size.extra_large.(4) The Ordinal method but the position of the enum constant in the enum declaration, where the position is counted from zero, for example Size.MEDIUM.ordinal () returns 1.7. Techniques for succession design(1) Placing public operations and domains in super-class(2) do not use protected domainsThis is because, first, the collection of subclasses

1. three main features of the process:Independence: With its own independent address space, a process cannot directly access the address space of other processes.Dynamic: is a collection of instructions that are active in a system.Concurrency: A single process can be performed concurrently on multiple processors, with no impact on each other.2. Differences in concurrency and parallelism:Parallel is the same time, there are multiple instructions on mul

= new MyThread1 (); Thread1.setpriority ( 1 = new MyThread2 (); Thread2.setpriority ( 10The result: high-priority threads are always executed mostly first, run faster, and do not mean that the thread's priority is independent of the order in which the threads are executed. This results in a 10 times-fold difference in priority. Change to a similar priority then look, like.Third, thread priority has randomnessMultiple runs o

. According to the function of the Division: node flow and packaging flow.four basic streams : Byte input stream, byte output stream, character output stream, character input stream BYTE stream Character Stream Output stream OutputStream Writer Input stream InputStream Reader The four basic streams are abstract classes : The other flows are inherited from the four main classes.We cannot create four base stre

Source of information: Software talent net Author: bristling super2002 I wrote an article on the Java implementation of the mail sent, when I wrote the message to send the function is very simple, can not bring attachments, can not have template. Later, a lot of friends asked me, there is no more perfect version, the existing mail sent me to write the design idea is convenient to send the attachment, you can send HTML pages including built-in pictures

The more efficient Java threads have always been, and then know the efficiency of execution and CPU core number, today we tried the multi-core CPU under multithreading calculation: This machine i5 four cores, opens 1, 4, 10, 20, 40, 100, 400 threads to do 100W times respectively, the result is as follows: All tasks

Java's core API is very large, which gives developers a lot of convenience, often people have comments, Java makes programmers dull. But some content I think is must grasp, otherwise can not skillfully use Java, also will not use "just silly". 1, under the Java.lang package of more than 80% of the functions of the fle

"); } @Override Public voidsleep () {System.out.println ("Puppy" +name+ "in Bed"); } @Override Public voidintroduce () {System.out.println ("Dog:color:" +color+ ", Age:" +age+ ", Name" +name+ ", type:" +type); } @Override PublicString toString () {return"Dog's name:" +name+ ", age; +age+ "years old, Kind" +type+ ", Color:" +color; }}//Cat Class Public classCatextendsanimal{String name; String sex; @Override Public voideat () {System.out.println ("Cat Eats fish"); } @Override Public voidsleep

Merge stream/Sequential stream (Sequenceinputstream):is to combine multiple input streams into a single Stream object.1 Public classSequenceinputstreamdemo {2 Public Static voidMain (string[] args)throwsException {3 //To create a sequential stream object4Sequenceinputstream in =NewSequenceinputstream (NewFileInputStream ("Stream.txt"),5 NewFileInputStream ("Stream2.txt"));6 7 byte[] buffer =New byte[1024];8