Java
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Java – NullPointerException in Avro reflectdatumwriter
I have a specific problem with Avro serialization of Java objects I have POJOs generated from the XSD schema, and then…… -
Creating dirty methods for threads in Java
I recently started to delve into multithreading in Java In the process of exploring things, I found that there are two…… -
Java – how to convert char [] to int?
I have a problem. I need to take an array of characters (only composed of numbers) and print its value as an integer p…… -
Java – different methods of passing parameters: String args [] or – D?
I've seen many Java use the - D option to pass some parameters The more familiar method is to pass the parameter with …… -
Can I add Ruby gem / module like a Java jar file?
I use eclispse Kepler and dltk plug-ins to make ruby I can't "request" the nokogiri module because eclipse can't find …… -
Java – more appropriately, amortized o (1) vs o (n) for inserting unordered dynamic arrays?
This belongs to stackoverflow COM / help / on topic's "software algorithm", in this case, is a software algorithm that…… -
Delete the object created in ArrayList in Java loop
I'm trying to delete the objects I created in ArrayList: turtles.add(new Turtle()); I want to get rid of the last turt…… -
Java – remove the back arrow button from the action bar
In my android project, whenever I go from first activity to second, I get a left arrow button, followed by some text i…… -
The Java input date from scanner is on one line
I'm trying to read the date from the user to pass to the Gregorian calendar variable At present, I have an embarrassin…… -
Multithreading – do I have to signal an anonymous thread if the main thread completes?
Is it necessary to explicitly stop all threads prior to exiting a Win32 Application? 5 procedure TForm1.FormCreate(Sen…… -
Java – list iteration – General Logic
I have a bean list (list < aclass >), from which I create two sub lists based on some logic, including checking …… -
Java deadlock when synchronizing on local resources?
I see the problem of multiple thread deadlock in the same line of code I can't understand why the thread is blocked on…… -
How do I apply calculations on the springs @ value property?
application.properties: application.properties: //timeout in ms timeout = 20000; @Value("${timeout} / 1000") private …… -
Java – ArrayList changes a property value of all objects
Java Spring Collection List<CustomObject> myList = new ArrayList<CustomObject>(1000); // list with thousnd…… -
Java – spring boot application failed to start
I recently started using spring boot to develop a web application, ANF, and tried to create these two files according …… -
Java – filter ArrayList with dates by start and end times
I am implementing a simple listview, where the data source is an ArrayList, which contains name, start and end dates I…… -
Java – how do I force MKDIR to overwrite an existing directory?
I need my program to create a directory with a specific name and overwrite any existing directory with that name At pr…… -
Java – Android NullPointerException when trying to retrieve data from sqliteopenhelper
When trying to retrieve all SQLite rows from sqliteopenhelper, I encountered the following error in logcat Caused by: …… -
Java – why does 10 > > 2 5 > > 2 evaluate to zero?
Consider the following codes: int a=10,b=5; int c=a>>2+b>>2; System.out.println(c); At run time, the (surp…… -
Java – use TreeSet for sorting without providing comparator
I know that TreeSet in Java will automatically sort its elements in ascending order to ensure the order For example, i…… -
Java – why does my socks proxy code throw a socketexception: a malformed reply from the SOCKS server?
Why does my socks proxy code throw a socketexception: a malformed reply from the SOCKS server? I tried on urlconnectio…… -
Java – spark job server: “the server cannot respond to your request in time”
I'm using spark job server to run spark jobs. It works normally But when I try to do a big job (it takes more than 40 …… -
Java – JBoss wildly and Jersey web service deployment error jbas011859: naming context is read-only
I am using Jersey servlet (1.18.1) to process Java Web services projects When I deploy my ear file to JBoss wildfly (8…… -
Java – a case insensitive sort set – maintains the same string in different cases
Today I have a case insensitive sort set, such as: Set<String> set = new TreeSet<>(String.CASE_INSENSITIVE…… -
Why Java io. File does not implement autoclosable?
See English answer > why Java io. File doesn’t have a close() method? 5 try (File file = new File(FILE_NAME)) { …… -
Java – how Jenkins finds out if a given slave server is running a job
I have this unique requirement to check whether a given node is running a job I'm thinking about using groovy because …… -
Java – GCM: how to send heartbeat to GCM server
I want to send a heartbeat from my application to the GCM server, so the connection will remain active How can I do th…… -
Volatile in double check locking in Java
See English answers > why is volatile used in double checked locking class Foo { private volatile Bar _barInsta…… -
Java – extract the first letter from each word in the sentence
I have developed a voice to text program where users can say a short sentence and insert it into a text box How do I e…… -
How to use Java Time parses the date in the string from the year and week
In old Java, I could do this: System.out.println(new SimpleDateFormat("yyyy w",Locale.UK).parse("2015 1")); // shows M…… -
Can an object array be regarded as a collection of objects in Java?
The collection definition of Oracle site is: A collection — sometimes called a container — is simply an object that gr…… -
Java – GlassFish 4.1 deployment failed on eclipse Luna using JDK 8
You cannot use JDK 8, GlassFish 4.1 to deploy GlassFish on eclipse Luna jsp. Exception stack trace: org.glassfish.tool……