Java
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Java – check whether a file is an image
I am using Jai and creating a file: PlanarImage img = JAI.create("fileload",myFilename); If the file exists, I check t…… -
Should I reset the Java heap space after use?
I'm using some modeling algorithms in R, one of which runs in Java (bartmachine) I found that before running the model…… -
Multithreading – managing threads in Grails services
So I have a service setting to import a large amount of data from the files uploaded by users I want users to continue…… -
Set null value in Cf9 ORM
Is there a way for Cf9 ORM to insert null values into the database instead of empty strings? I have a numeric field th…… -
Java – how to avoid initialization of large arrays
I assigned a lot of doubles double[] x = new double[ n ]; Where n is large, I want to avoid initialization to save tim…… -
Where can I get tools for use with earlier versions of Java 8 JDK jar
Where can I get tools from earlier versions of Java 8 JDK jar？ Without it, my java 1.8 Maven POM based project in Net…… -
Java threads in libgdx
Hey guys, I'm making a game with libgdx. I really want to operate the game, so I run a drawing loop and a logic loop o…… -
Java – is this class single?
Are the categories listed below singles? Since the constructor is declared public, can I infer that the class is a sin…… -
Java JPA: perforant checks whether the entity is already in the DB
What is the best method / best practice to use JPA to check whether an entity is already in the database? I'm writing …… -
How to suppress warnings during Javadoc compilation (within the scope of the code base)?
I'm stuck in a legacy java code base, and there will be thousands warnings when you compile it I am happy to actually …… -
Julia: append to an empty vector
I want to create an empty vector and append an array to Julia What do I do? x = Vector{Float64} append!(x,rand(10)) Th…… -
XMPP – how do I retrieve chat history using the Java smack library from the openfire server?
After installing the open archive plug-in in the openfire server, I can see that the chat conversation between two use…… -
Java – how do I add soap headers to the spring Jax WS client?
How do I add soap headers to the spring Jax WS client? Specifically, I have a JAXB object that I want to add to the ti…… -
Java – Android and lambda
I need to integrate some code with the widespread use of Java lambda functions The problem is that using lambda requir…… -
Java instanceof and class name
I just asked this curiously. Maybe it's meaningless When we use instanceof in Java, for example: if (a instanceof Pare…… -
Java – how do I access static members in a velocity template?
I don't know if there is a way to do this in velocity: I have a user POJO, an attribute called status. It looks like a…… -
What is the main difference between the optional Scala option of Java 8 and Haskell’s may?
I've read several articles about the upcoming optional types in Java 8, and I want to know why people keep suggesting …… -
Java – is entitymanager really thread safe?
I'm talking about the basic usage here: @Stateless public class BookServiceBean implements BookService { @Persistenc…… -
Java – under what conditions do we need to use composite keys in the database
I've seen that we can use compound keys, where the primary key consists of a combined primary key of two tables Like p…… -
Java – unable to resolve HttpServletRequest
I have imported the following I want to get the preferred language browser HttpServletRequest request = ServletActionC…… -
How do I convert year and week to Java date objects?
How do I convert year and week to Java date objects? I'm using jodatime, but it's also good to use the standard Java c…… -
Java – singleton using atomicreference
Is the deferred initialization singleton correctly implemented using atomicreference? If not – what are the possible p…… -
How to use Java stream to collect multiple lists into one list?
There is already an answer to this question: > java8 lambda: concat LIST1 List<MyListService> services; serv…… -
Java – what’s the big difference between using include or loop through lists?
Performance wise, there is really a big difference between use: > ArrayList. contains(o)vs foreach | iterator > …… -
Tuning GC for Java audio applications
I noticed that when playing audio in Java, the marksweepcompact phase in GC is too long and leads to short silence, wh…… -
Java – @ formdataparam not found in Jersey 2.17
I'm new to web services, so I've started the basic examples This one involves file upload I am using the latest (2.17)…… -
Java – passing methods as parameters – is this possible?
I tried to migrate to Java 8 and have some methods in my Dao class to do the following @Override @SuppressWarnings("un…… -
Java – mention and reorder the same thing?
Read from effective Java. Without synchronization, the following sequence a can be converted to sequence B by the virt…… -
java – android. permission. WRITE_ SECURE_ Settings error
Hello, my problem is that when I try to change the weather or no GPS settings are enabled, I get the following error 1…… -
Java – garbage collection and manual memory management
This is a very basic question I'll use C and Java to make it, but it's really language independent struct Obj { bo…… -
Java – spring asynchronous method called from another asynchronous method
I'm using spring 4 and I noticed a strange behavior... If I call asynchronous methods multiple times from a regular in…… -
Java – use BigInteger multiply operator
I wonder if there is a way to multiply BigInteger variables because the * operator cannot be applied to BigInteger So ……