Java
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Java – find unpaired numbers in an array
I have an array that repeats all elements except one: int[] a={2,6,2,4,1,4}; How do I find unpaired element integers? …… -
IO stream technology
Create and delete files: createnewfile(), delete() Create folders: mkdir() and mkdirs() List next level: lists the sub…… -
How to resolve file names in Java?
I have a java file path /opt/test/myfolder/myinsidefolder/myfile. jar I want to replace the file path with the root pa…… -
Java – how to add padding using container?
I tried to do some padding at the top, but how do I use the container? JFrame frame = super.screen.getFullScreenWindow…… -
How to use Qt5 to realize multithreading (I)
#include "thread_one.h" thread_one::thread_one(QObject *parent) : QThread(parent) { } void thread_one::run() { …… -
The value of Java jsonobject array is key
I'm new to Java, so it's a little confusing I want to get a string in JSON format What I want is { "user": [ "name","l…… -
Java hashcode() string conflict
I know little about hash codes I found that this code can print out collisions Can you tell me what collision is and h…… -
Java – allocate memory using thread
I wonder what happens if a local thread is declared in a method? Usually, after the function returns, all local variab…… -
How to solve this Java lang.ClassCastException：org. apache. tomcat. dbcp. dbcp. Basicdatasource cannot be cast to org apache. tomcat. jdbc. pool. DataSource？
I tried to use pool for database connection in Tomcat. This is my context: <Resource name="jdbc/slingemp" auth="Con…… -
Java – a document error that occurs when a node is appended to XML
public static Node createNodeFromXMLString(String xml) throws SAXException,IOException { public static Node createNode…… -
Java enumeration using enumeration in constructor
Can I have enumerations in Java take a set of enumerations as parameters? If so, how can I achieve it? When I use this…… -
Java – return statement in void method
I have the following method to return void. I need to use it in another method that also returns void @H_ 403_ 9@ @H_ …… -
String operation in Java
I asked the following two questions in an interview yesterday 1 GT; Given a string, calculates a new string in which a…… -
How to judge the efficiency of Java code
I just realized that from a computational point of view, I don't know how to judge whether a piece of Java code is val…… -
How does the Java link list loop using the for loop?
Hello, I'm trying to create a for loop that iterates through the linked list For each data, it will be listed separate…… -
How to use JTable’s row classifier to restore the original row order?
I have enabled sorting in JTable using the setautocreaterowsorter method Clicking the column header will switch betwee…… -
Java: bad operand types
I'm a beginner. I'm sorry if this question is stupid I wrote the following code: public class Traindata { String City;…… -
Java – how to use asserttrue?
I have: package com.darlik.test; import org.junit.Assert; public class Test { public static void main(String[] …… -
Java – how to sort hash map list
I have a HashMap list, as shown below ArrayList l = new ArrayList (); HashMap m = new HashMap (); m.add("site_code","A…… -
Java time implementation
package timeToys; package timeToys; import java.util.regex.Pattern; ** * A DayTime is an immutable object that sto…… -
Java – can you request multiple types at once?
Basically, I want to do this: public interface A { void a(); } public interface B { void b(); } public class S…… -
java – JMH puzzle：StringBuilder vs StringBand
It's hard for me to understand the progress of this benchmark I want to measure how my sample class stringband works c…… -
Java – if a runtimeException is thrown, can it be caught as an exception?
If I have a try block that throws a runtimexception subclass, can subsequent catch blocks catch it as an exception? es…… -
Java split string “^ ^” [copy]
See the English answer > java split on ^ (CARET?) not working,is this a special character? 6 ***^|^100^|^101^|^102^…… -
Java if() does not work
When I run some code (shown later), I tell it to check the string = = "1". If so, output "it is 1!", Otherwise, the st…… -
Java – which class is the superclass of all classes
I am a JAVA beginner I'm a little confused about the superclasses of all classes in Java? Solution From object documen…… -
Java and python ^ operators
For the CompSci class, we are looking at the Java math class As my stupid programmer, I try to use the ^ operator inst…… -
Java – scanner class hasnextline infinite loop
Why does this code enter an infinite loop when I try to give it a basic text file? import java.io.File; import java.io…… -
Java – what does “J” mean in a JApplet?
翻译错误 Invalid Access Limit Solution When sun started working on swing, they were like javax swing. Something like a…… -
Global sum error of multithreading in Java
I'm new to multithreading in Java. I made some code to see how it works I use global = 0 as the global int variable an…… -
Sorting point lists using java
See English answers > sort ArrayList of custom objects by property 25 Solution Yes, create a custom comparator and …… -
Java and windows – error: illegal escape character
I have finished changing registry data Java file But I'm running runtime getRuntime(). An illegal escape character err……