Recent Posts
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Java – is there a stateless version of JPA entitymanager?
Hibernate has a stateless version of its session: does JPA entitymanager have something similar? That is, an entityman…… -
Java – GlassFish: messagebodyprovidernotfoundexception in Jersey client
Hi, all I tried to create a rest web service from scratch This is my service part @Path("/Phones") public class Phones…… -
Java – how to fix com mysql. jdbc. exceptions. jdbc4. Mysqlnontransientconnectionexception: no operation is allowed after the connection is closed Exceptions?
This is a query for my records public void saveTotal(JTextField txtGtotal,JTextField txtPTotal) { try { Re…… -
Java – compare 2 integers, strange behavior
See the English answer > why is 128 = = 128 false but 127 = = 127 is true when comparing integer wrappers in Java? …… -
Arrays – function [hashtable []] parameter, which can be from pipeline or parameter
This is a function that accepts a hash table array through parameters: function abc () { Param([Hashtable[]]$tabl…… -
Java – what does t mean when used as a method signature? Is it a return type?
abstract public <T> T iterEdges(EdgeFun<T> func,T accum); abstract public <T> T iterEdges(EdgeFun<…… -
Java – regular expression failed to check whether the string contains non numbers
Why did this fail? String n = "h107"; if (n.matches("\\D+")) { System.out.println("non digit in it"); } I slept one …… -
Java – implement a nondeterministic finite automata (NFA)
I am trying to develop a simulation of non - deterministic finite automata in Java The first command - line argument i…… -
Java do loop increment
int i = 10; int i = 10; int j = 0; do { j++; System.out.println("loop:" + j); while (i++ < 15) { …… -
Java – get ultrasound from Android using frequency
I want to get ultrasound from any Android device, such as ultrasound with a frequency between 18khz and 19khz I use th…… -
Memory comparison of scala array [int] V / s int [] in Java?
Do they have the same memory? Array is an abstract class, so will it cause any object title cost? Are other Java primi…… -
Java – unable to run program “/ applications / utilities / terminal. App”: error = 13, permission denied
I encountered a lot of complex problems when running the following code: package practice; import java.io.IOException…… -
Distributed HashMap or distributed information storage in Java
Does anyone know a good java framework for distributed hash mapping (DHT)? I used overlay Weaver some time ago, but th…… -
Why Java io. File does not implement autoclosable?
See English answer > why Java io. File doesn’t have a close() method? 5 try (File file = new File(FILE_NAME)) { …… -
Java – filter ArrayList with dates by start and end times
I am implementing a simple listview, where the data source is an ArrayList, which contains name, start and end dates I…… -
Delete the object created in ArrayList in Java loop
I'm trying to delete the objects I created in ArrayList: turtles.add(new Turtle()); I want to get rid of the last turt…… -
Java – find K minimum integers in the array
This is my code, which is suitable for finding 1-7 minimum integers, but 8 and 9 When I find the eight smallest intege…… -
Java – why can’t I use generic types to implement non generic signatures
I'm a little confused about the java compiler I have an interface with "object" method signature: public interface Bea…… -
Java – protects int, visible only to the specified method
Is there any way to make me invisible to other methods in the same class? private int i; private void updateI(int i) …… -
R. Do all x elements exist in Y
In R, how to test the elements of a vector that does not exist in another vector? X <- c('a','b','c','d') Y <- c…… -
Symfony – the difference between get (‘doctrine ‘); And getdoctrine();
In symfony, I found three ways to access the doctrine service and entity manager, as shown below: $em = $this->getD…… -
Examples of scanner errors in Java books?
I'm practicing HashSet from the Java books of cay S. Horstmann and Gary Cornell, and I think there's an error in the s…… -
What does Java – (savedinstancestate) mean
There are some codes in my main activities if (savedInstanceState != null) { mCurrentSelectedPosition = sa…… -
Java – how to change the chart generated by Apache POI to not use smooth lines and display empty cells as gaps?
I use poi 3.12-beta 1, and the code can create a line chart containing multiple data sets and named Series in the lege…… -
Java – how to convert exchange attributes to uppercase in ‘simple’?
How do I convert attributes on Apache camel exchange to uppercase in the Apache camel expression language? for example…… -
Why is this wrong? About Java 8 streaming media
public interface Filter<M> { public interface Filter<M> { boolean match(M m); public static <…… -
How can I / O multiplexing be used to process requests asynchronously in a java server?
Suppose I'm writing a java server that communicates with clients over TCP / IP The server uses I / O multiplexing Ther…… -
Assembly – returns the location of the program counter after the interrupt handler?
Hi, I want to know where the program counter is when the program returns from the interrupt service program? I know th…… -
Java optional question, did I do this?
I have a "bad habit" of throwing zeros somewhere, such as enumerator when something doesn't exist Example: private enu…… -
Java – a case insensitive sort set – maintains the same string in different cases
Today I have a case insensitive sort set, such as: Set<String> set = new TreeSet<>(String.CASE_INSENSITIVE…… -
Java – spring boot application failed to start
I recently started using spring boot to develop a web application, ANF, and tried to create these two files according …… -
Java – more appropriately, amortized o (1) vs o (n) for inserting unordered dynamic arrays?
This belongs to stackoverflow COM / help / on topic's "software algorithm", in this case, is a software algorithm that……