包含标签：Java 的文章
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Java – Maven: exclude the “meta-inf / Maven” folder from the jar
I use Maven to build jars When I checked the jar, I saw a maven folder in the meta - inf folder I want it to be exclud…… -
String concatenation does not work in Java when concatenating two results of a ternary operator
Dear Java master! Please explain why concatenation does not work properly in Java when connecting two results of terna…… -
Java – programming the difference between POJOs and beans
I have the following two classes Can I say that the first is a POJO class and the second is a bean class? 1) POJO clas…… -
Why is the combiner function reduction operation not performed in the java-8 stream?
See English answers > java 8 stream – reduce function's combiner not getting executed Stream.of(1,2,3,4,5,6,7).redu…… -
Java – returns only the last element in the ArrayList
I've been teaching myself Java. I've always insisted on a problem. No matter what I do, it seems that I can't solve it…… -
Java – use groupingby for nested maps, but collect different types of objects
So I have the code for this "work" (replace some names for simplicity): Map<String,Map<String,ImmutableList<S…… -
How to use multiple streams and in Java 8 with lambda expressions Map function
I have a list County, which only contains the unique county name, and a list txcrarray, which contains the city name, …… -
Bean validation message with dynamic parameters
I started using bean validation, and I'm trying to build constraints My constraint is to verify CPF (personal file in …… -
Java – spring startup projects imported in IntelliJ do not work
I have imported the spring boot project generated by the spring boot initialiazr website, and I can't find the spring …… -
Java – ArrayList to array conversion – toarray() function infers that the type does not meet the upper limit error
This is the code simplet: Excel excel = new Excel(); ArrayList<Integer> a1=excel.readExcelSheet("C:\\Users\\Madh…… -
Java – why does my scanner still need a blank char
Input: 1 2 3 Objective: each number will be filled in the same array Space will be excluded Scanner in = new Scanner(s…… -
Java – JUnit: call @ after to set the object to null
Suppose I have the following simple JUnit test private Person person; @Before public void createObject() { String …… -
Java – if the return type of the rewriting method is original (such as double), can we change the return type of the rewriting method (such as int, char)?
As follows: Method to override: double add (int a,int b){ } Method of covering the above method: int add(int a,int …… -
Java – array initializers are not allowed here
I have some model classes. I try to declare a list with them, but I get that the array initializer is not allowed here…… -
Java – cut and stack arrays
I have an int array as input The length of the array is always 2 ^ n. I want to cut the array in half and stack it Rep…… -
Java cucumber: obtain @ cucumber options from external sources, such as property files
Whether it can be from Java Get the cucumber option value from the properties file? In this so post, it shows that it …… -
Java – Convert list to map and filter null keys
Using the Java 8 stream, I want to convert the list into a map as described in the solution of Java 8 list < V >…… -
Java — call Runtime. in the onLowMemory method. gc()
Should we use runtime GC () or system GC () to clear the memory in the production code in the onlowmemory () method in…… -
Java Runtime. getRuntime(). Freememory() problem
I searched and saw some threads, but none solved the specific problem I encountered I tried to use runtime getRuntime(…… -
Using java to convert children to parent problems
class Parent { class Parent { int i = 60; } class Child extends Parent { int i = 70; } class Main { pub…… -
Java – how do I use group mapping streams?
I have a long child // ordered by parent.id / child.id Stream<Child> childStream; Say, Child(id = 1,parent(id = …… -
Java – how do I check that the value is equal to at least one field in the list?
I have this method: for (String fieldName : fieldArray) { Query query = new Query(); query.addCriteria…… -
Java – 25 even and even random number generator
I need to generate 25 random numbers and divide them into two arrays, depending on whether they are odd or even This i…… -
How do I scroll down to click an element in Android using appium and Java?
I wonder how to scroll down to click an element in Android using appium and Java? I have a list of elements in "Androi…… -
Java – where does Maven search for log4j Properties file?
I am using log4j with Maven to face problems I have a properties file, log4j Properties, I put this file in the POM. N…… -
Java 8: default method for automatically synthesizing multiple interfaces
I have classes that implement multiple interfaces with the same default methods I want to know how to synthesize defau…… -
Java – spring: you cannot connect to JMX server from behind the firewall using RMI
My spring application runs on the machine behind the NAT firewall (pfsense) The internal IP of the machine is a.b.c.d …… -
Java-8 – pass the Java 8 stream mapping function as a parameter
I have a comma separated string that I want to convert to an array But in some cases, I need integer parsing, and some…… -
Java – how to visualize recursion
I try to understand recursion in Java through visualization I've taken some tutorials on youtube and used one of the e…… -
Repeated projection of Java nested mapping
Why does the actor work? import java.util.HashMap; import java.util.Map; public class TestMap { public static voi…… -
Java 8 lambda specifies the map type and makes it immutable
I have the following code, generated using Lambdas for several months Map<Integer,String> tempMap = new LinkedHa…… -
Java 8 stream – merge two sets to make them unique in a specific field [copy]
See English answers > java 8 distinct by property 20 This is the best I can do in Java, but it collects unique name……