Recent Posts
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Java – can heap memory usage be checked by pool?
I've been trying to optimize a program with many memory leaks The leak has now disappeared, but the occasional operati…… -
Configure the path style in the Java SDK Amazon S3
I am using AWS Java SDK provided by Amazon to interact with S3 service It seems that by default, the SDK uses the virt…… -
Java – why can only some XPath expressions find nodes when XML has a namespace prefix
In the following example code, any XPath of the form '/ / elementname' will return null when the source XML has a name…… -
Java – ‘Maven jetty: run’ how does it work?
What I learned is: >Jetty is a java servlet > Maven is a build automation tool mainly used for Java projects >…… -
Numpy – is there an equivalent of SciPy for 2D arrays signal. Deconvolve stuff?
I want to deconvolute 2D images with point spread function (PSF) I've seen a SciPy signal. The deconvolve function app…… -
Java – how to specify multiple fields as the primary key of an entity (using JPA)
See English answers > JPA composite primary key 2 Suppose we have a personnel table of SSN, nationality and name An…… -
java. Lang.noclassdeffounderror: in anonymous inner class
I use sun / Oracle JVM 1.6 on Linux red hat_ 23 run this code on a VMware server Sometimes the JVM seems unable to acc…… -
Java – mapping multi-level inheritance in Hibernate
At present, I have such a structure: A | +--B | +--C It uses join tables to map one table per subclass For historical …… -
Automatic startup of java desktop applications?
I created a desktop application in Java using NetBeans 6.1 and created a jar file of the application Now I want it to …… -
Java – how to handle exceptions of multiple routes
I'm mastering the spark framework, and I'm trying to understand the best way to handle exceptions in multiple paths At…… -
How to use JUnit to get database connection in spring?
I am trying to use the correct logic of services and methods to test the correct information provided by dB In this si…… -
Java – is there a way for IntelliJ to warn me that this code may cause NullPointerException?
Is there any way for IntelliJ to warn me that this may lead to NullPointerException? URL resource = Main.class.getReso…… -
How to use SQL Server Compact Edition (CE) of Java?
I want to access Microsoft SQL Server Compact Edition database from Java How can I do this? I searched the jdbc driver…… -
Populating an array with a common list using vendors in Java 8 throws classcastex B / C with type erasure
I want to use supplier and stream Generate populates an array with a generic list as elements It looks like this: supp…… -
Java – different output of ‘run’ and ‘debug’ when using readline()
I get two different outputs of the same code When I debug and step through each line (using NetBeans 8.1), I get a res…… -
Java – Apache Tika’s C / C + + alternative
I am looking for a C / C + + alternative to the Apache Tika framework based on Java Specifically, I am searching for f…… -
Java – calculates the maximum number of threads that can be used for better performance in ThreadPool
Recently, I was faced with an interview. The interviewer asked me what is the maximum thread you can assign to the thr…… -
Kill the thread on the running VM (JBoss instance) using Java?
A bug in a third party library causes an infinite loop in the working thread on my JBoss instance Do you know how to k…… -
Java – JPA @ ID and insertable = false, updatable = false throw exception
I'm using Oracle database. I have sequences and triggers to generate and store IDS before insertion CREATE SEQUENCE CA…… -
Java – what buffering strategy should I use for 2D scrolling maps?
So I'm creating a top - down 2D game in Java I follow the instructions of Java 2D: hardware acceleration – Part 2 – bu…… -
Java Swing: focus issues
I'm making a level editor for my game I have a property panel where I can modify the properties of the selected object…… -
Why is the Java division of integers faster than the joy of hackers
I'm testing the throughput of divs10 function from hacker joy book, in my JDK 1.7 64bit version 21 and i7 Intel @ R_ 6…… -
Multithreading – the parbuffer evaluation does not give the expected acceleration
I have a Haskell function, and I want to evaluate it with accurate intermediate results: f 0 x = 0 f n x = let tmp = f…… -
Unit test – parameterized JUnit test without changing the runner
Is there a clean way to run parameterized JUnit 4 tests without changing the runner, that is, without using I have uni…… -
Calling order of overloaded methods in Java
I'm studying some Java exams. I've encountered this problem: //Write the output of this program: public static void m…… -
Java – generates compiler warnings using user-defined annotations
Is it possible for the compiler to generate warnings when encountering user-defined comments? Something like the @ dep…… -
JFrame retain() problem – Java
I want to be able to draw using java paint () on JFrame When I click on the JFrame (anywhere now), I want to redraw th…… -
Recursive generic definition and stackoverflow in Java
I am writing implementations of deterministic finite automata for some research projects, and some arcs lead to the sa…… -
Java – convert resultset to excel (*. Xlsx) table using Apache poi
I'm trying to write the resultset to an excel (*. Xlsx) table using Apache poi Table object error in Office Excel inva…… -
Why Java Lang.void cannot be serialized?
By default, the primitive 'void' can be serialized. Why can't the object 'void' extend serializable? Add example: Root…… -
Java – gradle: conflict inclusion / exclusion of war missions
I'm trying to build a war file using gradle, but I have a problem. It excludes one directory and contains another dire…… -
Java – jdbctemplate multiple result sets
I tried to find a simple way to handle stored procedures / SQL returning multiple result sets I have been using the si……