how to practice coding in java

The following information was drawn from the project:Https://www.cnblogs.com/whenever/p/5526420.htmlHttps://www.cnblogs.com/jpwz/p/5715852.htmlHttps://www.cnblogs.com/sddychj/p/6102192.htmlhttps://zzk.cnblogs.com/s/blogpost?Keywords=java+socket+ Multithreading __requestverificationtoken= Cfdj8gf3jjv4cttdney2uyrcgz0kcosvpzzwlayvpu5r95d1oz8nhsq1qxox6l_ S0tdix36-vqfer-yemgbxg29wz0fs1ft-swezszh4opfatuvkj4sdctgegzuvkv9kknpiiyjcjtrprjpj2jiy8x7rzzhmulspblixf

1.1 Practice of methods1.1.1 Method exercises to get a larger of two data1.1.2 Case Code IVpackage com.itheima_01;import java.util.Scanner;/* * 需求：键盘录入两个数据，返回两个数中的较大值 * * 两个明确： * 返回值类型：int * 参数列表：int a,int b */public class MethodTest {// 返回两个数中的较大值public static int getMax(int a, int b) {if (a > b) {return a;} else {return b;}}public static void main(String[] args) {//创建对象Scanner sc = new Scanner(System.in);//接收数据System.out.println("请输入第一个数据：");int x =

= reader.getvalues ();if (str! = null str.length > 0) {if (str[0]! = NULL ! "". Equals (Str[0].trim ())) {List.add (str);}}}} catch (FileNotFoundException e) {Log.error ("Error reading CSV file.", E);} catch (IOException e) {Log.error ("", e);}finally{if (reader! = null)Close CsvreaderReader.close ();}return list;}The above code has several points:1 Specify delimiter and character encoding when initializing Csvreader, if not specified, the default is comma and iso-8859-1, I use GBK, depending

: Collect user actions and use this to recommend things that you might like.Aggregation: Collects files and groups related files.Classification: Learn from existing classification documents, look for similar features in documents, and categorize them correctly for untagged documents.Frequent itemsets mining: grouping a set of items and identifying which individual items will often appear together. Hcatalog. Apache Hcatalog is a mapping table and storage Management Service for Hadoop to build dat

priority-ordered blocking queue that can sort all placed elements (implementing the Comparator interface)29, when a method, can throw interruptedexception, means that this method is a blocking method, if it is interrupted, will prematurely end the blocking state.When you call a blocking method, it also means that itself is called a blocking method because you have to wait for the blocking method to return.If the blocking method throws an interrupt exception, what we need to do is to throw it to

is compared, if the same, it means that there has not been a write operation, the result of the original traversal is returned, if not the same, the process is repeated again, if not the same, It is necessary to lock all the segment and then one through. Public intsize () {//Try a few times to get accurate count. On failure due to//continuous async changes in table, resort to locking. FinalSegment This. Segments; intsize; BooleanOverflow//true if size overflows LongSum//Sum of mo

Kotlin is a new JVM-based language that can be seen as the extended language of Java, developed by JetBrains, who first saw him in the company's Android team when they saw them using the Kotlin to develop Android, suddenly feeling curious, and then slowly studied the prophecy.Why to develop and use the Kotlin language, the official saying is:Concise safeversatileinteroperableAnd cite an example:Nullif for youfun calculatetotal (obj:any) { if (obj is

(FileNotFoundException e) {e.printstacktrace (); } Catch(IOException e) {e.printstacktrace (); }finally { Try { if(in!=NULL) In.close (); if(out!=NULL) Out.close (); } Catch(IOException e) {e.printstacktrace (); } } LongEndTime =System.currenttimemillis (); LongSpendtime = EndTime-StartTime; System.out.println ("Method four, Bufferedinputstream and Bufferedoutputstream based on the addition of the cache array after the copy time:" + Spendtime + "millisecon

Daily development, operation and maintenance process often encounter the following issues: Under what circumstances do I need to output a log? How do I choose the log level when I explicitly need to output a log? What do I need to output in the log when I explicitly need to output the log? A tomcat loads multiple projects, how do you determine what works in the log? Multiple Tomcat loads the same project at the same time, can you use log4j Dailyrollingfileappender and other fil

Java serialization and deserialization (practice)Basic concepts:Serialization is the process of converting an object's state into a format that can be persisted or transmitted. Relative to serialization is deserialization, which transforms a stream into an object. Together, these two processes make it easy to store and transfer data.I saw it in a book yesterday, practiced it, serialized it as a generic file

} The result compiler will prompt an error. This is a very low-level error, but sometimes it will not be discovered: it is to try to rewrite the private method, but when we remove the override label, the compiler does not report errors and can execute the statements. In fact, the grow you mentioned in Apple is only a private Method for Apple itself. Is a new method. This raises a question: What is rewrite? In object-oriented systems, only interfaces and common methods can be used to repr

Write a Java program that calculates the circumference length and area of the RADIUS 3.0 and outputs the results.Note: The system class math is in the Java.lang packet, and pi π can be obtained by the static attribute pi of the math class, which is defined as "public static final double PI = 3.14159265358979323846;".1 PackageCom.hanqi;2 3 Importjava.lang.*;4 5 //Write a Java program that calculates the cir

Chapter 5 Programming Practice Analysis in the first quarter of Java 5-1 basic writing 　　 Automatic completion shortcut: alt +/ 5-2 Input and Output Use the score tool class to obtain user-input score Information The category class is located in the java. util package. You need to import this package when using it. Steps: 1. Import

integer object is created (1) integer i = 1; (2) Integer i = integer.valueof (1); If it is an object created in both cases, it will only create an object that is already cached in a integercache, so = = comparison is equal. If it is not in the range 128 to 127, regardless of the way the object is created, = = is always false, that is, their address will never be equal. 6. Automatic conversions are converted in order from low to high. The priority relationships between different types of data ar

InterruptedException { lock.lockInterruptibly(); try { return cancellableSendOnSharedLine(message); } finally { lock.unlock(); }}private boolean cancellableSendOnSharedLine(String message) throws InterruptedException {} 3. Locking of non-Block Structures Ii. Performance Considerations ReentrantLock provides better competitive performance in Java 5.0 than built-in locks.

always holds the correct lock when visiting the data.A closed mechanism is easier to construct a thread-safe class, because when the state of the enclosing class is parsed, the entire program is not required to examine the thread security of the class.Even if the closure can guarantee that all processing within the object is readily available, it is also important to note that when the object is advertised, it is possible to fail, such as hashset-only one variable in the sample object ensures t

the wrong understanding:Some say, "Using the String.intern () method, you can save a string class to a global string table, and if a Unicode string with the same value is already in the table, the method returns the address of the string already in the table. If you do not have a string of the same value in the table, register your own address in the table "If I interpret this global string table as Chang, his last word," if there are no strings of the same value in the table, then registering

Java's data types fall into two categories: basic types and reference types;The basic type can only save some constant data, the reference type can save the data, but also provide the function to manipulate the data;In order to manipulate the basic types of data, Java also encapsulates them, getting eight classes, which are the basic types of encapsulation classes in Java, respectively:Eight basic types: by

{@Override Public voidrun () { for(inti=1;i) {Random R=NewRandom (); intN=r.nextint (1000); Try{thread.sleep (n); } Catch(interruptedexception e) {e.printstacktrace (); } System.out.println ("I first" +i+ "Want to go:" +Thread.CurrentThread (). GetName ()); if(i==10) {System.out.println ("To Go is:" +Thread.CurrentThread (). GetName ()); System.exit (0); } } } Public Static voidMain (string[] args) {Thread th=NewThread (NewTest7 ()); Th.setname (Beijing); Thread Th1=NewThr

PackageLianxiti; Public classCat {PrivateString name; PrivateString color; Private intAge ; PublicString GetName () {returnname; } Public voidsetName (String name) { This. name=name; } PublicString GetColor () {returncolor; } Public voidsetcolor (String color) { This. color=color; } Public intGetage () {returnAge ; } Public voidSetage (intAge ) { This. Age =Age ; } //Behavior//Display Name Public voidShowName () {System.out.println ("The cat's name is:" +