包含标签：Java 的文章
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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…… -
Java – error: unable to initialize module treewalker – unable to instantiate junittestcase
After importing Maven project into eclipse Luna, the following error will pop up when saving after modifying the metho…… -
Java – how to use log4j2 login to close the hook?
Log4j2 also uses the close hook to end its service But, of course, I want to document the entire life cycle of my appl…… -
Java – key value storage recommendations
I need a very basic key value stored as Java I started to use HashMap, but it seems that some space in HashMap is inva…… -
Java – can I use refactoring to swap the type of another variable?
Android Studio provides powerful refactoring, such as renaming I can use it to change the names of variables, fields a…… -
Java – how to flip a letter upside down?
Here, I want to turn an English letter upside down my email template Then I can get it manually. What I'm doing now is…… -
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……