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 – 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…… -
Suggestions for finding end-to-end Java CPU profilers [closed]
What good end-to-end CPU analyzers exist in Java? Quick list I'm looking for: >Offline analysis – no user interacti…… -
Java – signal / slot mechanism
For people with relatively new Java ecosystems, is there a fairly lightweight way to perform the processing of their s…… -
Java – how to read line by line using FileReader
Thank you for your attention I created a program and I am using the login form and registration form Once users regist…… -
java – EJB3 / JPA @Transactional
Is there an EJB or JPA annotation equivalent to spring's @ transactional? Solution The equivalent EJB 3 attribute is j…… -
Java – how to make jtidy format HTML documents well?
I'm using jtidy v.r938 I'm using this code to try to clean up the page final Tidy tidy = new Tidy(); tidy.setQuiet(fal…… -
Is there a data structure / library in the memory OLAP / pivot table in Java / Scala?
Related issues This question is very relevant, but 2 years old: in memory OLAP engine in Java background I want to cre…… -
Jpa-2.0 – JPA cascading persistence – many to one
I have a one - on - one relationship and I'm trying to stick to a sub - entity public class Office { public int id; pu…… -
Java unchecked / exception clarification
I've been reading about unchecked and checked questions, and no online resource really knows these differences and whe…… -
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 – 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 8 – zoneddatetime is not equal to another zoneddatetime
I created two zoneddatetime objects, which I think should be the same: public static void main(String[] args) { Zo…… -
Java – how to configure spring boot applications to continue using resteasy?
I have an old web application (pure servlet without spring) and I want to run it as fat jar Solution You can use reste…… -
Is there a standard option or nullable class in Java?
Nullable (c#) has some different meanings, but in any case, option (Scala) and nullable can be used to express the con…… -
Java – understand the last value and value returned by try catch
I have the following code public static void main(String[] args) { System.out.println(returnString()); } private s…… -
What is monad emulation in Java?
I know that in scala and many other functional languages, monad is mainly an interface implementation (for example, us…… -
Java – strange gradle IntelliJ error
When I tried to import the gradle project in IntelliJ idea, the following error occurred: The beginning of the IDE log…… -
Java – resttemplate does not pass the origin header
I'm trying to use spring's resttemplate for cross - source requests Communication is done between two spring boot weba…… -
Java – Hide / filter nodes in JTree?
I have a data object in treemodel, and I want to show only a part of it in JTree - for argument, say leaves and their …… -
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 – 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 …… -
Java – is there a simple and safe way to convert a printwriter to a printstream?
Is there a simple way to use Java io. The instance of printwriter is converted to Java io. PrintStream？ Solution Firs…… -
What are the methods of drawing 3D trees using Java and OpenGL?
I know how to draw basic objects using jogl or lwjgl to connect to OpenGL What I want is something that can generate s…… -
How to use java to control the LED lights connected to PC through USB / SerialPort, etc? What equipment should I use?
I want to write a program in Java, which can control the LED light to connect to the "thing" connected to the computer…… -
Java – return try block in block vs return block
I have a try statement in a small static method. Is there a best practice for where I should return? try { mightTh…… -
Java – add some days for jodatime instant
I'm trying to write a simple utility method to add an integer day to joda time instant This is my first attempt /** *…… -
Java – disable all reports in Maven’s project info reports plugin
I want to generate custom reports through Maven's site plug-in, but only this custom report, instead of all reports ge…… -
Java – which is better when calling a function: twice or storing the result in a variable?
I doubted this problem many times, but I couldn't find the right solution I'll clear it this time I like something 1. …… -
Java – Android gets the PID of other applications
I want to be able to start an activity or service and get the PID of the process as soon as possible, which will be th…… -
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…… -
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……