Recent Posts
-
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 – 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 – 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 – 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 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 – 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 – 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 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 – ehcache does not delete elements from memory during eviction
> ehcache 2.5 maxEntriesLocalHeap="10000" eternal="false" statistics="true" overflowToDisk="false" timeToIdleSecond…… -
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 …… -
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…… -
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 – 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. 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…… -
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 – 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 – 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 – 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 – 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 – Thread. Getid() global uniqueness problem
If multiple Java applications are running on the system, each thread ID is unique relative to all other Java threads, …… -
Java – annotation processor – how to get the class it is processing
I'm trying to write a custom annotation processor public class AnnotationProcessor extends AbstractProcessor { .....…… -
Java – passing subclass instances as superclasses using JAXB
I have a set of Java classes representing message types (close to 25) They all inherit the message class that they wan…… -
Java – generics and classes >, EnumSet. allOf(class)vs class. getEnumConstants()
I have the following beanvalidation code that works properly and allows you to validate a bean annotation with: @EnumV…… -
Java – create a directory, if it does not exist, and then create the files in that directory
The condition is that if a directory exists, you must create files in that specific directory and create a new directo…… -
Java – compare and exchange
As the title indicates, I am looking for a comparison and exchange implementation, but it is relatively large: if(newV…… -
Java – save treeviewer state before setinput()
I tried to save the Jface treeviewer extension state to refresh it after calling the setinput () method I tried the se…… -
Java expression compilation error
See English answers > why is n + + + n valid while N + + + n is not? one int x=-3; System.out.println(x-----x);…… -
Java – if multiple threads are updating the same variable, what should be done to update the variable correctly for each thread?
If multiple threads are updating the same variable, what should I do to update the variable correctly for each thread?…… -
Java generic boundary type
Are the following two signatures the same? public static <T> void work(Class<T> type,T instance); and publ…… -
Java – streaming audio from PC to smartphone?
For Christmas 2016, my father and I want to make a light for our community with lights and music We have light setting…… -
Is time regression enabled in Java 9 EA?
I've heard of it >Each major version of the JVM becomes faster (in some ways) > 9 modularity will lead to faster…… -
Java – PDF report with embedded HTML
We have a Java based system that can read data from the database, merge various data fields with preset xsl-fo tags, a……