Java
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Java – Jackson – serialize Boolean to 1 / 0 instead of true / false
I have a rest resource to receive a JSON object, which is a mapping from a user ID to a Boolean value, indicating whet…… -
Java – why does a new string with UTF-8 contain more bytes
byte bytes[] = new byte[16]; byte bytes[] = new byte[16]; random.nextBytes(bytes); try { return new String(bytes,"U…… -
Model view controller – JavaFX includes fxml in fxml without controller
I am writing an application using JavaFX My scenario is defined in different fxml files Because I tried to use MVC mod…… -
Java Stream Collectors. Tolist() does not compile
Anyone can explain why the following code can't be compiled, but what about the second code? Do not compile private vo…… -
Java-8 – optional, do not handle null elements
When I experiment with optional < T >, I do not process null elements, so in the following example, it throws Nu…… -
How to add a scrollbar in JavaFX
I'm trying to add a scrollbar to H@R_869_2419 @Yes Scrollbar was added, but I didn't scroll How can I make it work? pu…… -
Java – get all rejected additions to set
I'm not very good at hashsets. I want to know if I can use them The addall method retrieves duplicates deleted by hash…… -
After adding the default method in Java 1.8, does the interface remain completely abstract?
After adding the default method in Java 1.8, does the interface remain completely abstract? I'm sorry if I can't state…… -
The list of Java objects is sorted by specific objects, not by
I have the following jsonarray trying to sort it So, to convert my jsonarray to ArrayList, then sort them and convert …… -
Cannot add an object of type T to the list in Java
I've been learning generics in Java Although I understand the concepts of type inference, parameterized classes and me…… -
Java – Android retro fit: missing method body or declaration abstraction
I'm writing an Android application that will use retrofit to make API requests I have such a helper class: public clas…… -
Java – boxed Boolean equivalent
Quick question: are you sure this code is always true? Boolean b1 = true; Boolean b2 = true; System.out.println(b1 == …… -
Is java “public static void main (string [] args)” the only way to create a main method?
I wonder if "Java main method" is the only way to create a main method in Java Java main methods: Solution The JVM nee…… -
How to initialize 2D string array in Java
I know how to declare arrays. I've done this: String[][] board1 = new String[10][10]; Now I want to do this. By defaul…… -
Java – build executables from different jars
I wrote a program that contains various Java libraries used in the program I used NetBeans to make the jar file of my …… -
Lambda – iterates over two lists using a Java 8 stream
How do I write the following in a Java 8 stream? int total = 0; for (ObjectA obja : rootObj.getListA()) { for (O…… -
How to make Java wait for user input
I'm trying to make an IRC robot for my channel I hope the robot can get commands from the console In order to make the…… -
Java – why is the difference between specific dates (03 / 12 / 2018) not the exact number of days?
I'm facing a strange problem with Java (versions 6, 7, 8) In this code, I try to calculate the date difference between…… -
Java – spring data JPA cannot be configured: the specified class is an interface
I have started using spring data JPA Unfortunately, I can't configure it I have entity class and repository interface,…… -
How to create a string representing Java as if it were an unsigned 64 bit value
My component was passed a long value, which I later used as a key in the cache The key itself is a string representati…… -
The Java iterator gets the next one without incrementing
I write the following loop in Java for each loop that I want to access the current and next elements of the link list …… -
How to cut the Java of each loop in half?
I'm working a lot for each loop in Java I'm using them to "draw" every class of my object, but it requires a lot of me…… -
Java – how to invert large arrays?
OK, so I know it's very easy to reverse the array by swapping items until you reach the middle like this: int array[SI…… -
Java-8 – three possible Java 8 optional values – how do you cleanly return any existing?
See English answers > teaching options in Java 8 5 return optionalA.orElseIfPresent(optionalB).orElseIfPresent(opti…… -
Avoid using global variables in Java 8 stream reduce methods
I'm trying to use Java 8 to rewrite the implementation of Moore's voting algorithm to find the major elements in the a…… -
Java – does the playframework return absolute URLs in HTTP instead of HTTPS?
I'm using only HTTPS in nginx play! A project is implemented in the framework Everything is normal, SSL is recognized,…… -
Lambda function in Java 8 has no parameters and return values
I want to transform a simple Java function into a lambda 8 function without any parameters, and then call it: public i…… -
Java – why must variables be initialized?
Here, I try to get the output month by entering the number of months, but why do I make a mistake Why must monthstring…… -
Switch statement found in Java method Does the method need to return something?
I was reading some Java textbooks trying to learn a new language, and I encountered this method private String monthNa…… -
Java – @ suppresswarnings annotation benefits
@Is the suppresswarnings annotation for clearer code, or is there any performance improvement or advantage by adding i…… -
Java – how to dynamically get fields from POJOs
The following is my POJO class, which has 50 fields with setters and getters Class Employee{ int m1; int m2; int m3; .……