Java
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Java – BigDecimal number format
BigDecimal val = BigDecimal.valueOf(0.20); BigDecimal val = BigDecimal.valueOf(0.20); System.out.println(a); I want to…… -
How to make a JavaFX image clipping application
I'm building an application for my colleagues to crop images Solution You have too many questions to be answered on st…… -
java – file. Createnewfile() IOException “no such file or directory”
Although java coding has this problem: file Createnewfile() throws IOException "no such file or directory" Check out o…… -
Java regular expression matcher mismatch
My string: <a href="https://MYURL/browse/TEST-53">FOO.BAR</a></p> Code: Pattern pattern = Pattern.co…… -
How to use pdfbox to digitally sign dynamically created PDF documents?
I'm sorry! I'm poor in Java Please correct me where I am wrong and improve where I am poor! I'm trying to use PDF@R_77…… -
Java – decimal conversion error
I'm writing a program to convert octal numbers to decimals It compiles correctly and everything, but my conversion cod…… -
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…… -
Huge string table in Java
I have a question about storing a large number of strings in application memory I need to load about 5 million lines f…… -
Java – the declaration of variable name declares the type of value to be stored? A prank?
Therefore, I have this true / false question in my computer science class (we use Java): (the word "type" in the quest…… -
Java – if I increase the memory heap, it will increase GC time
My current application runs on a normal GC cycle with 2GB of memory I want to increase JVM memory to 4GB to improve ap…… -
Java – why use the “this” keyword in constructors and setters?
Constructor is used to initialize a value and assign it to class variables when creating class instances, right? publi…… -
How to change only Java net. Protocol part of URL object?
I have a Java. Net that uses HTTPS protocol net. URL object, for example: https://www.bla.com I only need to change th…… -
Java – how to find the calling class?
How can I find out which class / method calls the actual method? Solution You can try to create an exception to get it…… -
I can’t figure out my simple java homework
I have this programming task, which can convert between meters and feet, and between kilograms and pounds When I told …… -
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: 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 – how to disable playback 2.6 csrffilter
I was recently migrated to 2.6. When I called my API from the postman about filters, I got 403 replies At first, when …… -
Java – save values in a loop
I'm trying to read the value of my country array string, which reads CSV files InputStreamReader reader = new InputStr…… -
Java – wait(), notify() – which thread is unlocked first?
Try to understand wait() and notify() I know when thread a enters wait (). It will be awakened by notify () from other…… -
Java arithmetic
Why does this code return the wrong value? int i=Integer.MAX_VALUE+1; long l=Integer.MAX_VALUE+1; System.out.println(l…… -
How can I disable a node without graying it out in JavaFX?
My problem is that I can disable nodes so that users cannot interact with them when printing However, for the same rea…… -
java – Collectors. Set implementation in toset()?
See English answers > what is default set / list implementation with collectors in Java 8 stream API? 1 Stream.of(1…… -
Java – what are the uses of objects of type object
I saw the code below the exercise in the scjp book Object obj = new Object(); First of all, I think this may be a mist…… -
Java 8 – restrict the flow of the first object and convert it to a specific object?
I used earlier: List<Person> person = UserDB.getUserDetails(); Person p = person.get(0); // index of first posit…… -
Lambda – converts the string list to a sorted map string length as the key
I have a list < string > and I have to convert it into a map. By grouping strings of the same length into a list…… -
Java – similar to camera Parameters. Gethorizontalviewangle() and camera Parameters. What is the Android Camera2 API of getverticalviewangle()?
All this is in the title, but in the now deprecated Android camera API, there are two methods: camera Parameters. Geth…… -
Java – Method override
class A class A { int i=10; void show() { System.out.println("class A"); } } class B extends A { int i=…… -
Verify the URL in Java
Who knows how to use regular expressions to verify the URL format in Java? thank you Solution A very sneaky way is: tr…… -
Java – even in flush()/. Filewriter will not write to the file after close()
I tried to write a text file, but even if the method creates the file, if it doesn't exist, it won't write I have pass…… -
Why does the Java ArrayList class return a Boolean value to add?
My teacher gave me this analogy to the method I was writing I still don't understand why the add method returns a Bool…… -
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 – 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……