Java
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Java – JPA – delete children from the onetomany relationship
In the @ onetomany relationship, if I want to delete a child, do I need to explicitly delete the child from the parent…… -
Java – overrides tostring() using overridden tostring()
Basically, that's what I want to achieve classname @ address(？) [original tostring()], the name of the object and the…… -
Java – Bayesian network in Scala
I am looking for a library to create Bayesian networks and learn and reason in scala (or Java, if there is no better s…… -
Java – what does “reference implementation” mean?
I'm trying to learn the cachedrowset in Java, and I'm reading some tutorials about it for example Who can please be ki…… -
Java – what happens when l (long) – = f (float)?
See English answers > floating point arithmetic not producing exact results 7 public class SimplePrint { public st…… -
Java – how to read BufferedReader two or more times?
I have a text file, one integer per line – 10 20 50 I want to read and print these numbers twice or more I tried some …… -
Java – why get base class methods through reflection when subclasses override them?
I have super classes: class MyClass<T> { public void setValue(T value){ //insert code } public T getV…… -
Java – a handler that does not add an HTTP header to an HTTP request when using the axis client API
I am using the axis API to access the axis HTTP server I use the following code to add a handler to the server The typ…… -
Java – classloader will not be garbage collected even if there is no GC root
We have one in GlassFish v2 Complex applications running under 1.1 In order to dynamically load our code, we implement…… -
Java – static initializer and instance initializer and constructor
There is already an answer to this question: > use of initializers vs constructors in java8 Solution The main diffe…… -
Java – spring data: can I include subqueries in query annotations?
I wonder if subqueries (org. Springframework. Data. JPA. Repository. Query;) can be used in the @ query annotation I g…… -
In Java / Apache httpclient, you cannot use vertical / pipe bars to process URLs
If I want to handle this URL, for example: post = new HttpPost("http://testurl.com/lists/lprocess?action=LoadList|4018…… -
Java – preconditions library throws illegalargumentexception for notnull check
Do you know that Apache commons validate or guava preconditions is a good alternative. When checking whether the objec…… -
Java-8 – delete the “05:30” section from java8 localdatetime to xmlregistry calender
As shown below, LocalDateTime currentUTCTime = LocalDateTime.Now(ZoneId.of("UTC")); String reqPattern = currentUTCTime…… -
Java – accessing private fields of another object in the copy constructor – is that really a problem?
In my java application, I have some such copy constructors public MyClass(MyClass src) { this.field1 = src.field1;…… -
Java – change date format
If the input is 01-01-2015, it should be changed to 2015-01-01 //Class to change date dd-MM-yyyy to yyyy-MM-dd and vic…… -
Java – spring boot devtools gets ClassCastException from the cache
I'm having trouble getting value from the cache java.lang.RuntimeException: java.lang.ClassCastException: com.mycom.ad…… -
Java – where can I find the base64encoder class?
Hi, I saw an example with this code on stackoverflow: String encoding = Base64Encoder.encode ("test1:test1"); HttpPost…… -
Java – how to make Maven build fail on duplicate dependencies?
If I have two identical dependencies in the same POM, I want the build to fail At present, I can use Maven dependency …… -
How do I catch all checked exceptions (in a single block) in Java?
Editor: this problem only involves Java 1.6 (and below) I'm sorry I didn't make it clear in the original post The hier…… -
Java: enumeration and if then else performance
I didn't have real luck. I used Google to get this concise answer rather than my time-consuming evaluation. I thought …… -
Java – optimistic locking and org hibernate. StaleObjectStateException：
I'm just trying to be optimistic I have the following courses: @Entity public class Student { private Integer id;…… -
Java allocated memory leak
I must assume that the following methods do not leak memory: public final void setData(final Integer p_iData) { da…… -
Java – confluence persistence
When writing your own macros, is there a simple built-in method to maintain data in confluence? This data needs to be …… -
Java object serialization – thread safe?
I am writing a highly concurrent application that extensively modifies MyClass objects The course consists of several …… -
Consider storing serialized Java objects as Cassandra as JSON What is catch?
I'm using Cassandra 1.2 2. I find it easy to use Jackson to map my objects and store JSON and Java in the database I'm…… -
java – OpenCV 2.4. 1：UnsatisfiedLinkError
I have an Android project with native code In this native section, I use OpenCV It compiles without any errors, but wh…… -
Java – resolve “duplicate definition of library class” in Proguard
I have a java project that contains the Xerces library When I process a project with Proguard, I receive a warning: No…… -
Java EE – how to instantiate multiple CDI / weld beans for a class?
In spring, you can instantiate any class by defining the corresponding bean in XML conf You can also instantiate multi…… -
Java – how to run methods asynchronously using spring?
The following code assumes asynchronous work, but waits for the async part to complete and then continues How do I mak…… -
Java – missing preview tab in birt layout
A new version of birt 4.0 has just been installed in eclipse x. The preview tab was not found in the layout window Sol…… -
How to protect methods in Java (overflow, etc.)
I have to write a "watchdog" in Java to ensure that threads do not take long to execute There is no problem with objec……