java-8

问题 So as it goes in the current scenario, we have a set of APIs as listed below: Consumer<T> start(); Consumer<T> performDailyAggregates(); Consumer<T> performLastNDaysAggregates(); Consumer<T> repopulateScores(); Consumer<T> updateDataStore(); Over these, one of our schedulers performs the tasks e.g. private void performAllTasks(T data) { start().andThen(performDailyAggregates()) .andThen(performLastNDaysAggregates()) .andThen(repopulateScores()) .andThen(updateDataStore()) .accept(data); }

问题 This question already has answers here : Rethrowing an Exception: Why does the method compile without a throws clause? (6 answers) Closed 3 years ago . I came across a weird scenario in java today while coding around. I have a try..catch block in my method which does not have any throws clause and I am able to throw the exception object caught in the catch block. It is an object of the Exception class, hence it is not an unchecked exception. Also, It is not printing the stacktrace if

问题 This question already has answers here : Rethrowing an Exception: Why does the method compile without a throws clause? (6 answers) Closed 3 years ago . I came across a weird scenario in java today while coding around. I have a try..catch block in my method which does not have any throws clause and I am able to throw the exception object caught in the catch block. It is an object of the Exception class, hence it is not an unchecked exception. Also, It is not printing the stacktrace if

问题 I need some clarification about how minor gc collections behave. calling a() or calling b() in a long-lived application, if they could behave worstly when old space gets bigger //an example instance lives all application life cycle 24x7 public class Example { private Object longLived = new Object(); public void a(){ var shortLived = new ShortLivedObject(longLived); // longLived now is attribute shortLived.doSomething(); } public void b(){ new ShortLivedObject().doSomething(new Object()); //

问题 This question already has answers here : Remove duplicates from a list of objects based on property in Java 8 [duplicate] (9 answers) Closed 18 days ago . I want to remove duplicates from a list like bellow List<DataRecord> transactionList =new ArrayList<DataRecord>(); where the DataRecord is a class public class DataRecord { [.....] private String TUN; and the TUN should be unique 回答1: There are two possbile solutions. The first one is to override the equals method. Simply add: public class

问题 I have a old application running a Swing client. I upgraded from Java 7 to 8 a long time ago. The upgrade went fine. Ever since I have wanted to upgrade to Java 9, then 11 and now 13. However this is where I meet problems. The UI looks fine and as intended with Java 8, but any newer Java version will somehow change the font sizes and maybe components for some reason. I do not have any pictures to show because the application is maintained on a network without internet access because of

问题 This question already has answers here : Specifying java version in maven - differences between properties and compiler plugin (3 answers) Closed 12 months ago . I'm facing a build error when I try to run a Maven build. I created a simple Java project which includes lambda functions, due to this I'm getting [ERROR] (...) lambda expressions are not supported in -source 1.5 [ERROR] (use -source 8 or higher to enable lambda expressions) My Java version is 1.8.0_172, my Maven version is 3.6.0.

问题 I have list of strings, where each string consists of letters separated by the character ',' (comma). I want to go through the list of strings, split on comma, and calculate how many times each letter occurs, and store the result in a Multiset. Blank strings should be ignored, and the split parts should be trimmed. The multiset should be sorted on key. The below code works, i.e., it produces the desired Multiset. However, I couldn't figure out how to use the proper collector method (Multisets

问题 In my Action Bean I load Entities from a database, use data from those Entities to create new EntityObjects using Java 8 ParallelStream, and store those EntityObjects in a List for later use on a web page. I use the following to create these Objects using the Hibernate mapped Entities: List<Entity> entities = dao.getEntities(); List<Object> entityObjects = new ArrayList<>(); entityObjects.addAll( entities.parallelStream() .map(EntityObject::new) .collect(Collectors.toList()) ); with a

问题 Java 11 JAVA_HOME : C:\Program Files\Java\jdk-11.0.4 I was able to find Java version in cmd with following command: java --version //successfully executed java -version //successfully executed Java 8 JAVA_HOME : C:\Program Files (x86)\Java\jdk1.8.0_231 I was able to find Java version in cmd with following command: java -version //successfully executed while I was unable to find java version with --version command java --version //not successfully executed Why I get error that Java Virtual