Java
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Java – is this singleton thread safe?
I have a singleton server instance, and I'm curious if my code is thread safe I've read for different singleton modes,…… -
Java file compilation with file extension
When we compile Java programs, we use javac file Java commands, but we use java files at runtime So why is it necessar…… -
Java – use auto assembled beans in objects created at run time
I have a class B that implements the w interface It has a default implementation of the W method Classes C and D overr…… -
Reusing resultset objects in Java
I'm working on a swing project I use JDBC ODBC connection bridge to access the data in SQL database I use the followin…… -
Java Swing Games perform poorly when many sprites are on the screen
I'm making a simple tower defense game in swing. When I try to place many elves (more than 20) on the screen, I encoun…… -
Java – pass enum member to constructor: “actual and formal parameter lists are different in length”
I'm confused. I think what I do is very stupid. I just can't see it! Central heating control: Radiator class and radia…… -
Java – simulate spring bean
I have the following courses: public class Plugin { private DistributionManager manager; public void init(){…… -
Java – compile errors using scanner
This is my current course: package Mathias; import java.util.*; public class Scanner { public static void main(S…… -
Java – how do I get the first five values from the linkedhashset?
I have a linkedhashset that contains multiple values LinkedHashSet<String> lhs = new LinkedHashSet<String>…… -
Java: how to use currenttimemillis() to obtain a long time and output it in X decimal places?
I have a representative system Long. Of currenttimemillis() Then I'll measure it later in the code I've subtracted two…… -
Java – wicket – which ORM?
I am looking for an ORM that is easy to use and integrated for wicket applications I'm thinking about hibernate Is thi…… -
Java – variables are instantiated in kotlin only when kotlin is empty?
It can be said that I have a variable: var myObject：MyObject？ = null It should be cleared somewhere: myObject?.clear…… -
Java – how to prevent HashMap or treemap from replacing previous values
If it already exists, how can I prevent HashMap or treemap from replacing the previous key value? In addition, I want …… -
How to create an autocomplete pop-up window in jtextpane in Java?
I am creating an SQL editor I am using jtextpane as the editor I want to implement autocompletion for table names such…… -
Java encodes the file as a Base64 string to match other encoded strings
private static String encodeFileToBase64Binary(String fileName) private static String encodeFileToBase64Binary(String …… -
Incredible little decimal best Java object
What Java object is best for storing tiny decimal values, such as 10 ^ - 25? When using minimum space, which object ho…… -
Java – is there any way to test 2-way SSL through the browser?
If so, how to set the authentication certificate and what files do you need? Yes pfx？ How would you install it in you…… -
Java – a faster way to find the key for a given value from the map?
I want to find the key of a given value from HashMap. At present, I have to pass all keys and check its value in the m…… -
Java – fast string search, such as startswith() is not equal to ()
I have a sequence list (a dictionary – 100k words) and many words are often searched in this list Therefore, performan…… -
Why is the string method substring () not in camelCase in Java?
According to Java standards, we should follow camelCase But why is the string method substring () not in camelCase? Is…… -
Print a list in Java?
I want to print a list in Java @H_ 301_ 8@ @H_ 301_ 8@ r1 r2 r3 r4 This is the code: @ h_ 301_ 8@ @H_ 301_ 8@ public s…… -
Java – what is the best remote technology for mobile applications?
I have a Java backend that needs to expose services to clients running in the following environments: > J2ME > W…… -
Being confused by Java generics requires a cast
I'm confused about the following code: import java.util.ArrayList; import java.util.LinkedList; import java.util.List;…… -
Java – ArrayList and indexof problems of my objects
I have an ArrayList problem with Java I created an object that contains two attributes X and Y. now I loaded some obje…… -
Java: how to create a loop to create an array?
I need a lot of arrays, now I create them manually: int[] row1 = new int[3]; int[] row2 = new int[3]; int[] row3 = new…… -
Java – wicket – which ORM?
I am looking for an ORM that is easy to use and integrated for wicket applications I'm thinking about hibernate Is thi…… -
Java – find element or check if it exists in array / list?
I'm a novice. I really don't understand how this works I made a list of room information: List<Room> rooms = new…… -
Java – the question I tripped over in the interview
I was asked several Java interview questions. I don't know how to solve them. I can use some answers >Write a metho…… -
Can Java constructors construct subclass objects?
Is there any way to modify the class constructed in the constructor? public class A { A() { //if (condition) ret…… -
Java – how do I check for memory leaks?
Can I check for memory leaks without entering the code I have my application and I want to check for memory leaks In m…… -
Java – how to read a user’s char on the command line
How to read the user's char from the command line I am familiar with readint() There is no such thing as character Thi…… -
Java – structured stream exception when using additional output mode with watermark
Although I am using watermark (), when I run my spark work, I receive the following error message: From what I saw in ……