Java
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Java – JPA @ onetoone throws an error when mapping to an abstract @ entity with subclasses
I have a problem when an entity maps to another entity that has a direct implementation on its subclasses See the foll…… -
Java – match an array of objects using mockito
I'm trying to set up a simulation for a method that requires an array of request objects: client.batchCall(Request[]) …… -
Java generics – class or class
I am writing a program that will dynamically create class instances based on user input using java reflection (i.e. cl…… -
Java – fit image to rectangle
If I have an image that I know the height and width, how can I put it in the largest rectangle without stretching the …… -
Java – why InetAddress getLocalHost(). Gethostname() returns a value different from bash “hostname”?
I have a build The gradle task works like a champion on my development box, generating a properties file that records …… -
Java – dynamic class conversion from interface to implementation
I've read other related posts, but I'm still not sure how or whether it can be implemented dynamically in Java My impr…… -
java – com. mchange. v2. resourcepool. Cannot acquire resourceexception: resourcepool cannot get resources from its primary factory or source
I have MySQL under hibernate, and I also use c3p0-0.9 1 connection pool When I run on a laptop (I mean local) I have n…… -
Java – use system Identityhashcode (obj) – when? Why?
When is the right time to do line 4 instead of line 3? Or do they repeat the call completely? 1 Object o1 = new Objec…… -
Java – output timing problem
The following codes: String str1="asdfavaxzvzxvc"; String str2="werwerzsfaasdf"; Object c=str1; Object d=str2; System.…… -
Java – what is a precompiled JDBC Preparedstatement?
A declaration of what "precompiled" is because I've seen it So if precompiling a prepared statement does not check the…… -
Java – HQL unexpected ast node:
My code cannot be injected into the following repository Based on stack trace, it seems that my HQL syntax is invalid,…… -
Java – how do I refresh Maven dependencies from eclipse?
We recently started using Maven for dependency management Our team uses eclipse as the IDE Is there a simple way to ge…… -
Java – how do I check if NULL is in the stream?
I have a stream < integer > and want to know if there is space in this stream How to check? use. Anymatch (null)…… -
java – Spring Security AuthenticationCredentialsNotFoundException,SecurityContextHolder. Getcontext is null
I have a strange mistake, a few hours of debugging, I don't understand Update 1: I use spring security 4.0 3. Run on T…… -
Java – how to update the expression datatable in a specific cell
I am creating a dynamic data filled with input fields Sometimes, when a user inserts a value into some input, a specif…… -
Java – can I have multiple profiles in the dropwizard?
I want to install several yaml files for the dropwizard One of them contains sensitive information and one non - sensi…… -
Java – duplicate JTable values in rows
I have a JTable filled with a custom datamodel (pasted below). When I call the populate () method, it seems to fill th…… -
Java project path to NetBeans text file
I have the following code to read a text file public static void main(String[] args) { try { Scanner in =…… -
java – Gson. Deserialize an integer to an integer instead of double
I have JSON objects with arbitrary values I want to deserialize it in the map Everything is fine except converting int…… -
Java – call thread Sleep () and * interrupt status * settings?
Java documentation is unclear at this point After calling thread What happens if an interrupt is called on a thread be…… -
Java – how to calculate the intersection between two or more hashsets?
Consider the following code and the fact that four hashsets are populated elsewhere My goal is to include all the elem…… -
java. Net website is closed and the Jersey document cannot be accessed
I can't get from https://jersey.java.net/ Access Jersey documentation Move Jersey files to a new location? Solution St…… -
Certification – Java – pbkdf2 and hmacsha256 as PRF
I was given the task of creating a login API for our project. I should use pbkdf2 and hmacsha256 as PRF The plaintext …… -
Java – error: unable to determine the type parameter of T during Maven installation
I have this feature that throws strange errors when I try to do an "MVN installation" public <T> T get(final AN_…… -
Java – dump the state of a variable in case of an exception
I want to know if there is a way to dump the state of all local variables when an exception occurs, so as to better un…… -
Java – use request Getsession () as the lock object?
I have some java code to get and set a session property: Object obj = session.getAttribute(TEST_ATTR); if (obj==null) …… -
Java – ArrayList containing different objects of the same superclass – Methods for accessing subclasses
Hi, I want to know if there is a simple solution to my problem, I have an ArrayList: ArrayList <Animal> animalLi…… -
Multithreading – what is Scala’s equivalent to clojure’s atom?
Clojure has an Atom for changing state between threads in a synchronous and independent manner,that is not part of the…… -
What is a good free tool for investigating unintentional object retention in Java?
My multithreaded Java program crashed because it ran out of heap space. I don't think it should Assuming that criminal…… -
Java – create a response using the location header in jax-rs
In NetBeans, I automatically generate classes with restful templates from entities and crud functions (annotated with …… -
Connection between Java string and operator
I'm confused about string connections String s1 = 20 + 30 + "abc" + (10 + 10); String s2 = 20 + 30 + "abc" + 10 + 10; …… -
Java – ehcache does not delete elements from memory during eviction
> ehcache 2.5 maxEntriesLocalHeap="10000" eternal="false" statistics="true" overflowToDisk="false" timeToIdleSecond……