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 – is my code too repetitive?
I'm studying my text adventure game and wonder if there's an easier way to write repeated code blocks, such as what I'…… -
How to set an infinite loop and break it (java thread)
I've set up a thread and I want to run it using a loop Therefore, this thread should run in the loop, interrupt within…… -
Java – how do I create a GUI in Android instead of using XML?
I don't like managing XML and Java together. Can I use the Java language to create the same GUI? Solution Yes, you can…… -
Java – Method println (int) in printstream type is not applicable to parameters (string, int, int, int)
public static void main(String[] args) { public static void main(String[] args) { int num1 = 1; int num2 = 1; …… -
Apply the function to each nth element in the vector
I have a vector in R: > v <- c(5,10,15,20,25,30,35,40,45,50) I want to apply a function to every Nth element of …… -
Java – is it possible to find out whether the value exists twice in ArrayList?
I have an integer ArrayList ArrayList <Integer> portList = new ArrayList(); I need to check whether I have enter…… -
Import the textfile and read it line by line in Java
I want to know how to import a text file I want to import a file and read it line by line thank you! Solution I don't …… -
Java double gets all numbers after dot / comma
This is a simple task, but I can't solve it myself I have double digit1 = 12.1; double digit2 = 12.99; And need a …… -
Can I use variables in Java to name variables?
What I want to do is have a loop each time to name a certain number of variables Therefore, sometimes when I run the p…… -
Java – generate WADL from existing CXF rest Service
I implemented Jax - RS service with CXF How can I generate WADL? Or is there anything like http://path.to.your/restapp…… -
Java – what is better shallow or deep cloning?
I'm a little confused about object cloning in Java What is the main difference between shallow cloning and deep clonin…… -
Repetitive sequences in Java / Python / Mathematica
How to write the following statements in a given language? a(0) = 1 a_(n+1) = 1 - 1 / ( a_n + 3) When a_ When n – >…… -
Java – check Batis mapper bean error
There are spring and mybatis network projects I use IntelliJ idea for development Review comments: Could not autowire.…… -
Convert text files to Java sets using commons or guava
I want to load every line in the file into the HashSet collection Is there a simple way? Solution how: Sets.newHashSet…… -
Java – RMI server exception
When I try to run a server using a remote registry, I get the following exception from RMI The registry code of my mai…… -
Java – the difference between classes and packages
What is the difference between classes and packages in Java? Solution Class is a declaration (usually an implementatio…… -
java – Integer. Parseint() does not resolve large negative numbers
When I try integer Why is numberformatexception thrown when parseInt ("80000010", 16)? This is a 32 - bit number, whic…… -
Java – Android replaces multiple characters from a string
I know it may be an amateur problem, but for some reason, I don't remember how to do it String s ="["; String q ="]"; …… -
Is the result of mathematical operation on Java – double completely repeatable?
I have a complex data processing algorithm, using java 8 and double as the data type Given the same input (hundreds of…… -
Java — on doubles and equality
I have a method that returns a double When I tested this method as part of JUnit, I noticed the following oddities: St…… -
Java – is an if else tree the best approach in the following situations?
What am I doing: I'm creating a simple calculator in Java that reads a string written in postfix notation (for example…… -
Thread problem in Java HashMap
Something happened that I'm not sure should work Obviously it's because I've seen it, but I need to find the root caus…… -
Java – a naming convention for variables that work like constants
I have a variable that I'm using like a constant (it never changes) I cannot declare it as a constant because the valu……