Java
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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 – read from InputStream and write to OutputStream
This should be very simple. I searched Google, but I didn't see anyone mention the problems I noticed Everything I've …… -
Java – use “this” in another constructor
Suppose you have a class with this constructor: public SomeObj(int x,int y) { this.x = x; this.y = y; } Everyt…… -
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() { …… -
Java – how does Android set a string array to a single textview
I want to try setting the string array to the text of textview How can I do this? Here's what I've tried so far: Strin…… -
In Java, which is the most recommended class for dictionary data structures?
I need a data structure to store users that should be retrieved by ID Solution It may depend on how many users you pla…… -
Java – JPA / eclipse link – retrieve column names
I'm trying to update my java knowledge because I was last in 1.4 When used in version x... I'm trying to use 1.6 0, es…… -
Java – many methods that cover many classes in one class
public class EventController extends MouseAdapter implements ActionListener { public class EventController extends Mou…… -
Java – can I change the shape of JButton?
Can I change the shape of JButton from rectangle to circle? Solution I think this may be what you're looking for: http…… -
Java – “startswith” is faster than “indexof”?
I write code in Java to cycle through the dataset at the same time according to whether the string starts with some ch…… -
Java – about sorting algorithms applied to stacks and queues
I wonder why we always use sorting algorithms (such as insert sorting or merge sorting,...) only for lists and arrays?…… -
Why does Java require char variables to use single quotes?
Why does Java require char variables to contain anything in single quotes instead of double? An example: char s = 's';…… -
Java – when using thymeleaf, the spring security sessionscope appears to be null
When the login fails with spring security, it will throw an exception and display it in my JSP, as shown below: <c:…… -
Thread contention in Java
I want to know the following procedure If I call new readerthread() Start() it works normally, but if I call new reade…… -
Java inheritance problem
Suppose I extend a class and override the methods in that class What is wrong with calling rewriting from my new class…… -
Java – use system out. Println() creates a border
Anyway, has this arrangement been created, and no string variable SH3 affects the boundary? I'm really sorry that my k…… -
Remove the JFrame from the taskbar in Java
I made a quick theme look, but I didn't find anything similar My query is: how do I prevent child windows from appeari…… -
Java – why not always increase the operator’s work on chars?
Why char c = 5; int i = c++; However, this causes a compiler error (invalid arguments / –) for the operator: int i = a…… -
Java – why does eclipse display errors in the play framework rendering method?
I received an error: public static Result home(String name) { return ok(home.render(name)); } Eclipse s…… -
Java – how to get parameters from the URL in Liferay portlet?
I used something like feed in Liferay 6 JSP of out of the box portlet such as jspf: String articleId =null; HttpServle…… -
Failed: metadata error: Java Lang.runtimeexception: unable to instantiate org apache. hadoop. hive. metastore. HiveMetaStoreClient
I closed my HDFS client while HDFS and hive instances were running Now, when I re-enter hive, I cannot perform any DDL…… -
Java – find the size of the file in the gzip file
Is there any way to find out the size of the original file in the gzip file in Java? As in, I have a 15 MB file a.txt,…… -
Storing DPI and paper size information in JPEG using java
I have the following code: ImageIO.write(originalImage,OUTPUT_TYPE,resultOutput); This is for the following javax imag…… -
For multiple lock attempts, use Java concurrent. ReentrantLock
I noticed the following code block: final Lock s = new reentrantlock(); for(int i = 0 ; i < 1000 ; i++) { …… -
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Java – how to convert dates to UTC
I need to change the date format to UTC format … I need to convert the LastModified date of the file in UTC format Sol…… -
Java – style EditText for Android
I ran Android 2.3 on my phone and noticed many applications that use ICs to edit text fields, such as square up and Tu……