Java
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When we assign integer to int in Java, why doesn’t the compiler make an error
When we assign integer (object) to int (primitive), why does the compiler not make an error? int i; Integer ii = new I…… -
Java – why can I unexpectedly create multiple instances of my singleton class?
According to my knowledge, singleton design pattern means that we can only create a single object of one class The fol…… -
Java – can I create a bitmask for ~ 100 constants?
Does this mean that the 100th constant must be 1 < < 100? Solution You cannot do this directly because the maxim…… -
Java – super fast autocomplete using binary search in sort files (300000 lines)
In my android app, I want an input field with autocomplete The number of projects is about 300000 The best solution se…… -
Java: trying to get the percentage of integers, how to sort it out?
I have two integer values, X and the sum I tried to find the percentage of total X That's what I'm doing now: Percenta…… -
Java – excludes folder names from eclipse file searches
How do I exclude a folder name from eclipse file search (ctrl h)? For example, if I want to search all files but exclu…… -
Switching cases with string Java
After using java for a long time, I found that, unlike other languages, Java does not support switch cases with string…… -
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 – how to schedule a task every “n” seconds in the spring framework
How to connect to my web XML task occurs every N seconds In addition, I need to refresh the server method every 5 seco…… -
Are there any Java APIs or built-in functions to solve annuity problems?
My boss asked me to create a module to calculate reverse compounds The question is: if I want to achieve $1.000 in 24 …… -
Java – the trouble of iterating HashMap using JSF, myfaces, and facelets
I had some trouble looping through HashMap to print its values to the screen Someone can check my code carefully to se…… -
Java split string “^ ^” [copy]
See the English answer > java split on ^ (CARET?) not working,is this a special character? 6 ***^|^100^|^101^|^102^…… -
Java – compile Hadoop 2.2 0 work?
It seems that all the examples are built considering the old version How to compile my java program on Ubuntu so that …… -
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…… -
How to use file. XML in Java Mkdirs () writes elegant code?
I need a directory to save the file, but I'm not sure if it exists File saveDir = new File("/tmp/appname/savedir/"); i…… -
Java – business logic of the client
Why do people say that business logic should be implemented on server-side code (such as EJB) rather than on client-si…… -
Java – Android WebView, zooming content to fit the screen
My friend created an application using JavaScript and uploaded it to his website Now I'm trying to wrap it in WebView …… -
Java – multipart resolver does not process multipart requests
I recently made some changes to my spring application by adding CSRF support To do this, I must also change the way I …… -
Java – why doesn’t my code compile which string starts with a vowel check?
if (flipped.charAt(0) = "a" || "e" || "i" || "o" || "u"){ if (flipped.charAt(0) = "a" || "e" || "i" || "o" || "u"){ …… -
Java – how to allow users to drag and drop releases in vaadin tables?
I have a multi - row table with custom components I want to allow users to delay the release I tried the following cod…… -
Java – sort the vectors of custom objects
How to sort the vectors of custom objects and select the attributes to sort? I do see this question & answer, but …… -
Java – one to many one-way parent-child ID cascade saving
When I try to save the ID from the parent class to the child class, I keep getting errors I tried all types of mapping…… -
Java – JPA onetomany list cannot find mappedby attribute that should be inherited
We are currently making some requirements. We must add some similar entities (car pictures, pet pictures, holiday pict…… -
Java – endpoint with OAuth: get the current ClientID
I just started using endpoints in Google App Engine, and everything seems to work well My API rejects non whitelist cl…… -
Java – how do I check the number of objects created in heap memory?
I want to see how many objects Java creates when running the program My intention is if I use the code string s = new …… -
Java – eclipse type erasure
I have a method defined like this: public <T> T methodName(Class<T> clazz) My unit test I mistakenly teste…… -
Java collection filtering
I have such things: public class Foo { public String id; } and Vector<Foo> foos; I need to get an object from …… -
Java – type set is not universal; It cannot be parameterized
My eclipse faces this strange problem Type set is not universal; It cannot be parameterized with the parameter < in…… -
Java – is JDBC secure?
I am a novice in JDBC. The new project requires me to use JDBC What I want to know is, Is JDBC secure? How to prevent …… -
Java – clarification of “int” numbers starting with 0
public class Test { public class Test { public static void main(String[] args) { int i = 012; Sys…… -
ArrayList in Java
ArrayList<String> veri1 = new ArrayList<String>(); ArrayList<String> veri1 = new ArrayList<String……