Issue When trying to just make sure the connect is working, this error arises. Error that pops up This is the connect string, Connection string This is my aapp.properties, spring.data.mongodb.uri=mongodb+srv://jamescervamtes:jamescervantes@theshop.rmeawrn.mongodb.net/TheShop spring.data.mongodb.database=TheShop I tried everything, and I am just expecting for
Continue readingTag: java
How to create bean based on property in springboot
Issue I have two beans in my application configuration. I would like to enable only one bean based on property, Can we make bean conditional based on property ? Ex: Let say if I have this property enable.userconnection: true, I
Continue readingSpring Data Elasticsearch (4.x) – Using @Id forces id field in _source
Issue Summary Recently we upgraded to Spring Data Elasticsearch 4.x. Part of this major release meant that Jackson is no longer used to convert our domain objects to json (using MappingElasticsearchConverter instead) [1]. This means we are now forced to
Continue readingSpringBoot with Thymeleaf – css not found
Issue First to say is that I’ve been searching for a solution for a while now and I’m quite desperate now. I cannot get the css file to be accessible from html page when run by Spring Boot. html.file <html
Continue readingAccess to XMLHttpRequest at 'http://localhost:8080/blog/updatePost/2' from origin 'http://localhost:3000' has been blocked by CORS policy:
Issue Even though I used @CrossOrigin annotation this error still appears. Spring boot app is running on 8080 port and react app is running on 3000 port. Error: If further information is needed, please let me know. Solution I assume
Continue readingCould not fetch model of type 'BuildEnvironment' using Gradle distribution
Issue I’m getting the below error when I have imported a gradle project and tried refreshing it. I’m new to gradle and using gradle wrapper. also, the gradle distribution exists in the repository. Could not fetch model of type ‘BuildEnvironment’
Continue readingHow to add a bean in SpringBootTest
Issue The question seems extremely simple, but strangely enough I didn’t find a solution. My question is about adding/declaring a bean in a SpringBootTest, not overriding one, nor mocking one using mockito. Here is what I got when trying the
Continue readingHow to point a single spring actuator endpoint to the root ("/")
Issue I have a requirement to expose a health endpoint on the root path on the specific port. However, root path is reserved for the actuator endpoints overview and I could not find a way to overwrite that overview functionality
Continue readingWhen and where to use JUnit, Mockito and Integration testing in Spring Boot Application?
Issue I’m very novice to Unit Testing, I have created a Spring Boot Application and now I want to do some testing what’s confusing me is where to use what e.g. I have classes and interfaces Controllers, Service, Repository I
Continue readingSwagger-ui.html is giving blank page
Issue When I am trying to enable swagger in my spring boot application, it is showing blank page. I am using url https://localhost:8080/context-path/swagger-ui/ I am able to get the JSON data for url https://localhost:8080/context-path/v2/api/docs I am not getting where this
Continue readingShedlock integration with Cassandra – CqlSession – table can not be null
Issue I am trying to integrate shedlock in my spring boot project using a cassandra db. But I am getting the below error on application startup. 2022-11-18 17:35:29,162 [main] ERRR o.s.boot.SpringApplication – Application run failed org.springframework.beans.factory.BeanCreationException: Error creating bean with
Continue readingHow to add requestHeader to the generated interface with openapi-generator-maven-plugin
Issue I am using openapi-generator-maven-plugin to generate the server code for a springboot application. However I can’t figure out a easy way to generate the @RequestHeader("header") in the interface. Here is the plugin configuration: <plugin> <groupId>org.openapitools</groupId> <artifactId>openapi-generator-maven-plugin</artifactId> <!– RELEASE_VERSION –>
Continue readingSpring custom configuration annotation
Issue I’m trying to create a Annotation to enable custom Kafka configuration to construct a commons lib. My idea with this aproach is turn easy kafka configuration for all my apps, removing all boilerplate configurations. So I want to annotate
Continue readingSpring Security exposing AuthenticationManager without WebSecurityConfigurerAdapter
Issue I’m trying incoming Spring Boot 2.7.0-SNAPSHOT, which uses Spring Security 5.7.0, which deprecate WebSecurityConfigurerAdapter. I read this blog post, but I’m not sure to understand how I can expose the default implementation of AuthenticationManager to my JWT authorization filter.
Continue readingSpring Security Resource Server throws "SpelEvaluationException: EL1011E"
Issue I’m setting up a Resource Server with Spring Security 5.7.3 which authenticates against a Spring Authorization Server 0.3.1. I followed the instructions on https://docs.spring.io/spring-security/reference/servlet/oauth2/resource-server/jwt.html by setting the isser uri (which seems to work properly) but I always get an
Continue readingHow to fetch data as pageable with custom query in Jpa without IllegalArgumentException?
Issue I am fetching data with custom query by applying the way on this post. And here is my repository method that returns a page sorted by distance which is a mysql function: @Query(value = "SELECT *, ST_Distance_Sphere(ST_GeomFromText(?1, 4326), location)
Continue readingSpring @configurable NullPointerException, @autowired service is null
Issue I’m trying to use @configurable in spring to use a @autowired service in a non bean class I create. It doesn’t want to work anymore whatever I try. Can someone tell me what I’m doing wrong? (I did some
Continue readingSpring @configurable NullPointerException, @autowired service is null
Issue I’m trying to use @configurable in spring to use a @autowired service in a non bean class I create. It doesn’t want to work anymore whatever I try. Can someone tell me what I’m doing wrong? (I did some
Continue reading404 error on logout with WAR exploded to Tomcat
Issue My application works fine when I use embedded Tomcat (with IntelliJ) but when I deploy WAR file on Tomcat 8 one of my URLs response with 404 (I can sign in into my application but logout with URL responses
Continue readingHow to create immutable and singleton class in Spring boot?
Issue I have a person model class that needs to be immutable and singleton. I need to autowire from my service class but getting an error. So is there any way to create a singleton immutable class in spring boot?
Continue readingFactory method 'jwtAccessTokenConverter' threw exception; nested exception is java.lang.IllegalArgumentException:
Issue It’s an error that comes out during spring build. I changed the difference from the existing source code to mariaDB -> mysqlDB. I wonder why this error is coming out. org.springframework.beans.factory.BeanCreationException: Error creating bean with name ‘org.springframework.security.oauth2.config.annotation.web.configuration.AuthorizationServerEndpointsConfiguration’: Invocation of
Continue readingJDK 17 spring boot Unable to make private java.time.LocalDateTime
Issue I have private LocalDateTime lastModifiedDate property in the simple mongodb entity. Run application with latest 2.5.5 and openjdk 17 Following exeptions I have with date time Caused by: java.lang.reflect.InaccessibleObjectException: Unable to make private java.time.LocalDateTime(java.time.LocalDate,java.time.LocalTime) accessible: module java.base does not
Continue readingSpring Boot/Gradle/Logback: bootRun fails with "Failed to instantiate [ch.qos.logback.classic.LoggerContext]": java.lang.AbstractMethodError:
Issue In a new Spring Boot application, when I gradle bootRun, I see this error: Failed to instantiate [ch.qos.logback.classic.LoggerContext] Reported exception: java.lang.AbstractMethodError: ch.qos.logback.classic.pattern.EnsureExceptionHandling.process(Lch/qos/logback/core/Context;Lch/qos/logback/core/pattern/Converter;)V at ch.qos.logback.core.pattern.PatternLayoutBase.start(PatternLayoutBase.java:86) at ch.qos.logback.classic.encoder.PatternLayoutEncoder.start(PatternLayoutEncoder.java:28) at ch.qos.logback.classic.BasicConfigurator.configure(BasicConfigurator.java:50) at ch.qos.logback.classic.util.ContextInitializer.autoConfig(ContextInitializer.java:164) at org.slf4j.impl.StaticLoggerBinder.init(StaticLoggerBinder.java:85) at org.slf4j.impl.StaticLoggerBinder.<clinit>(StaticLoggerBinder.java:55) at org.slf4j.LoggerFactory.bind(LoggerFactory.java:150) at org.slf4j.LoggerFactory.performInitialization(LoggerFactory.java:124) at
Continue readingHow to kill Java thread when it is finished?
Issue First time I am working with threads in spring boot webapp and when I do debugging then I see thread names are increasing like Thread-1, Thread-2… for every call method so I thought that the program is not killing
Continue readingWhy throw the same Exception and do nothing with Log result?
Issue At work a goal of mine is to be more involved in code reviews since I went to school for computer science and studied theory, etc. My coworkers all have picked up java through courses supplied from work, and
Continue readingslf4j logging – difference between the two error logging methods (with and w/o Throwable)
Issue I am using slf4j 1.7.x for logging in our Java project. The Logger interface has multiple methods to log at ERROR level such as these two: void error​(String msg, Throwable t) void error​(String format, Object… arguments) My question is,
Continue readingHow to add the timestamp of the fatal error occurrence to Java fatal error log filename
Issue Background You can use java -XX:ErrorFile=/path/to/file to specify the path of fatal error log file. You can use the -XX:OnError option to execute a command when an error causes on a Java VM. To maintain the fatal error logs,
Continue readingSystem Outs and Un handled exceptions from Java App is not having a timestamp when logged
Issue Need help here. We have java apps started from our shell scripts in unix using java command and the output is redirected to a nohup file to ensure we capture any SystemOuts and any unhandled exceptions in a log
Continue readinghow to handle long click in Android
Issue I am new to Android dev. The way I have been handling clicks has been by setting the android:onClick attribute in the manifest file for buttons. What I am wondering is the best way to handle long clicks in
Continue readingAndroid onCreateContextMenu Fatal Exception by longclick on ListView item
Issue I try to create Context Menu for my List View, but when i do “long-click” on List item, application shut down with this trace: FATAL EXCEPTION: main java.lang.NullPointerException at com.android.internal.policy.impl.PhoneWindow$DecorView$ActionModeCallbackWrapper.onCreateActionMode(PhoneWindow.java:2445) at com.android.internal.app.ActionBarImpl$ActionModeImpl.dispatchOnCreate(ActionBarImpl.java:708) at com.android.internal.app.ActionBarImpl.startActionMode(ActionBarImpl.java:392) at android.app.Activity.onWindowStartingActionMode(Activity.java:4380) at com.android.internal.policy.impl.PhoneWindow$DecorView.startActionMode(PhoneWindow.java:2151) at
Continue readingRemove by longclick on row from ListView (SQLite database)
Issue I Try for long hours to delete a row from a listview (SQLite). What I was able to do until now ? Showing all the data by rows on the listview. Long click on one of the rows showing
Continue readingDisable Reoplening Activitiy Mulitple Times on Map Long Clicks
Issue I am making an app that enables a user to long click on map, and open a new activity that would allow them to add a new tag and info about it. When user long clicks once, if he
Continue readingAndroid – Why does onItemLongClick(…) return a boolean?
Issue Coming from a Java background I am used to dealing with actions though I’m not really sure why the method requires a boolean is returned and don’t fully understand the explanation given on the site: true if the callback
Continue readingLong Click Does Not Work On ListView rows
Issue I want to be able to long click ListView cells so that an AlertDialog pops up and lets me delete a row in the ListView. However, the long click does not register. I even tried setting userChatroomListView.setLongClickable(true) below is
Continue readingDetecting a long press in Android
Issue I am currently using onTouchEvent(MotionEvent event) { } to detect when the user presses my glSurfaceView is there a way to detect when a long click is made. I’m guessing if I can’t find much in the dev docs
Continue readingPersistent push with comet long-polling on Jetty?
Issue I am trying to create a Jetty servlet that allows clients (web browsers, Java clients, …) to get broadcast notifications from the web server. The notifications should be sent in a JSON format. My first idea was to make
Continue readingTomcat 7 server error after 10 seconds when long polling
Issue I’m trying to achieve long-polling in Java web application. The application is written using Spring MVC 3.2 and I make use of DeferredResult object (it represents Servlet 3.0 async response capability). The problem is that when using DeferredResult I
Continue readingManually set transport type on a Spring + Sockjs application
Issue I need to install an application on a non JEE7 compliant server. I am using Spring + Stomp + SocksJs for realtime notifications. My code looks like this: @Configuration @EnableWebSocketMessageBroker public class WebSocketConfig extends AbstractWebSocketMessageBrokerConfigurer { @Override public void
Continue readingUsing Redis Stream to Block HTTP response via HTTP long polling in Spring Boot App
Issue I have a spring boot web application with the functionality to update an entity called StudioLinking. This entity describes a temporary, mutable, descriptive logical link between two IoT devices for which my web app is their cloud service. The
Continue readingCorrect way to implement long polling using OkHttp3 and ReactiveX Java
Issue How do I implement long polling using OkHttp3 (v4.4.1) to get RxJava (v2.2.11) Observable for each line of the response? Can it be done without blocking a thread to keep reading lines? If I need to block some thread
Continue readingHow to implement Long Polling REST endpoint in Spring Boot app?
Issue Would you be so kind as to share any up-to-date manual or explain here how to implement a REST Long Polling endpoint with the latest Spring (Spring Boot)? Everything that I’ve found by this time is quite out-dated and
Continue readingAmazon SQS Long Polling not returning all messages
Issue I have a requirement to read all messages in my Amazon SQS queue in 1 read and then sort it based on created timestamp and do business logic on it. To make sure all the SQS hosts are checked
Continue readingRefactoring crazy inheritance hierarchies of value objects – How to get a list of all fields and types?
Issue So basically, I need to manually adjust an inheritance hierarchy. I’d like for the classes to be perfect, no extra fields, and they’re just DTO’s. However, it’s really easy to get lost and add duplicate fields, and it’s really
Continue readingHow to make DatePickerDialog maintaining selected user date when changing screen orientation?
Issue In an opened DatePickerDialog, when screen orientation is changed, it reset the selected user data. (the DatePickerDialog does NOT CLOSE and it does not maintain the selected data) Code: public class ActivityNeki extends FragmentActivity { DialogFragment newDF = null;
Continue readingHow to set page orientation for Word document?
Issue I use Apache POI XWPF to create and handle MS Word documents. But I didn’t find in the documentation how to change the page orientation. Apparently this way should make it: XWPFDocument doc = new XWPFDocument(); CTDocument1 document =
Continue readingLimit path media type mappings in Jersey
Issue I have configured MEDIA_TYPE_MAPPINGS for my Jersey apps. Unfortunately, this causes some trouble with a generic upload service in my app. @PUT @Path(“files/{filename}”) @Produces({ MediaType.APPLICATION_XML, MediaType.APPLICATION_JSON }) public Response uploadFile( @PathParam(“filename”) @NotNull @Size(max = 240) String filename, DataSource dataSource)
Continue readingsort Alphanumeric values regardless of letters
Issue input –> "123","01","123A","728R" ,"1234" Output should be 01,123,123A,728R,1234 i tried the below but not giving expected OP. public int compare(SO o1, SO o2) { if(o1.getnumber() != null && o2.getnumber()!=null) { if (NumberUtils.isNumber(o1.getnumber()) && NumberUtils.isNumber(o2.v())) { Long val1 = Long.valueOf(o1.getnumber());
Continue readingSort 2D array by average value of each line
Issue I have complex task to differently sort two dimensional array manually. So far I get done those tasks: User needs to input row size from 10 – 20, Generate 2D array where row size is user input and column
Continue readingHow do I read a .txt file into a 2D array in java?
Issue I can’t figure out what’s wrong with my program. I want to read a .txt file named "salesReport" into a 2D array, but it only reads one line. The 2D array has 10 rows and 12 columns, and I
Continue readingLong Press Android to Java
Issue I’m trying to program a Mouse via Wifi TCP. Client is on Android and Server on Java. I’m trying to detect a LongPress on Android and send this information to Java. Android: I need to implement MotionEvent.ACTION_DOWN but I
Continue readingHow to separate Button Longpress Button press Up and Down events
Issue I have a Click function and long press on the same button. Implemented the long press event but, I need to find the button UP_EVENT and DOWN_EVENTS separately. How can I implement by using the OnLongClickListener View.OnLongClickListener listener =
Continue readingI want to delete items on ListView when longpressed
Issue I want to delete items on a listView when longpressed. In this code you can add (with edittext) a list item with Button, as you can see below. I have been unable to write the code for deleting them
Continue readingDozer mapping non-Generic Collections to properties
Issue I have some class structure as follows. These classes are hibernate classes so I cant change them. //assume all getters & setters are present public class Order{ private Customer customer; } public class Customer{ // non generics set private
Continue readingwebservice returning Object1.java not the same as Object1.java in the client app?
Issue The same object is defined twice in different packages: packageX/Object1.java and packageY/Object1.java [Background: packageX is part of a webclient service, getting objects from a server. packageY is a java client using the objects retrieved by this webclient service]. A
Continue readingConversion of Java object, containing 2 or more maps, to JSON using jackson
Issue Given a class of the following format: Class A { Collection(Item) x= new ArrayList(Item)(); Collection(Link) y= new ArrayList(Link)(); . . //You can add data to the Item and Link classes } where we have Class Item { int x;
Continue readingIn Java can you create an unordered collection of objects that have multiple links?
Issue I’m trying to make a game similar to Risk where each territory on the map is an object of a class I made, Territory. In order to create the game map I would like each Territory object to be
Continue readingConvert a part of Json to HashMap using Jackson ObjectMapper
Issue I am trying to unmarshall a json file in a way such that few properties of Json are mapped into a HashMap that is present in my model class.Rest of the properties are mapped to the respective fields of
Continue readingCan not deserialize instance of Object out of START_ARRAY token
Issue I have two object one is Dashboard and second is Room i have a json which is look like this { “hotel_id”:”1″, “hotel_room”:”200″, “hotel_properties”:[{ “id”:”1″, “room_type”:”Single”, “rack_rate”:”2000″, “publish_rate”:”1800″, “discount”:”10″, “availiable”:”40″, “total”:”50″ }, { “id”:”2″, “room_type”:”Double”, “rack_rate”:”4000″, “publish_rate”:”3600″, “discount”:”10″, “availiable”:”45″,
Continue readingJava Modelmapper: Converter doesnt get used
Issue im working on a little java-program that synchronizes active directory users with users in my db. therefor, i am using modelmapper. seems to be working fine and is also pretty fast. anyway i added a converter to my mapping
Continue readingMapStruct: Object.class to Custom.class mapping
Issue I’m a newbie with MapStruct, and need some help with that. I have a Source class, with an attribute Object input; Which, in runtime, returns a custom object named TicketDetails. Now, in my target class there is a attribute
Continue readingSelma map List<T> to T
Issue I am using Selma and I have the following class: public class Customer { private int id; private String email; private String firstName; private String lastName; private Date registeredDate; private List<Address> addresses; } I want to map it to:
Continue readingNoClassDefFoundError in simple test
Issue I want to use moo for dto- entity conversion. But testing it i get this exception Exception in thread “main” java.lang.NoClassDefFoundError: org/mvel2/PropertyAccessException at com.codiform.moo.configuration.Configuration.getTranslator(Configuration.java:62) at com.codiform.moo.session.TranslationSession.getTranslator(TranslationSession.java:131) at com.codiform.moo.session.TranslationSession.translate(TranslationSession.java:122) at com.codiform.moo.session.TranslationSession.getTranslation(TranslationSession.java:64) at com.codiform.moo.curry.Translate.from(Translate.java:63) at Main.main(Main.java:15) Caused by: java.lang.ClassNotFoundException: org.mvel2.PropertyAccessException at
Continue readingDozer mapping two classes with mismatched argument counts
Issue I have two beans, one has five attributes and the other has four. How do I configure the mapping if I simply want to ignore the extra attribute? All of the exclude examples I see take an argument for
Continue readingModelMapper – Failed to convert ArrayList to List
Issue I have the following Beans public class Ticket extends BaseEntity { private ForeignCollection< TicketDetail > ticketDetails; } public class TicketDto extends BaseDto { private List< TicketDetailDto > ticketDetails; } And I’m mapping, using ModelMapper, a List<TicketDto> to a List<Ticket>
Continue readingMapStruct: Mapping 2 objects to a 3rd one
Issue I have Object1 and Object2. Now, I want to map object3, with attributes from 1 & 2. Say, I have 2 object: 1. User: {first_name, last_name, id} 2. Address: {street, locality, city, state, pin, id} Now, with these, I
Continue readingCan't map property when using MapStruct
Issue I am using MapStruct library to map objects but I got this error: Can’t map property “java.util.Date aDate” to “javax.xml.bind.JAXBElement ADATE”. Consider to declare/implement a mapping method: “javax.xml.bind.JAXBElement map(java.util.Date value)”. My question: WHERE should I decleare this mapping method?
Continue readingMapping a hierarchy of entities to a hierarchy of DTOs using Orika
Issue Is it possible to map an object to its corrisponding DTO when both belonging to a class hierarchy? For example: I have a BaseEntity and some ExtendedEntity1 .. ExtendedEntityN On the other side I have a BaseDTO and some
Continue readingUsing MapStruct SPI custom AccessorNamingStrategy with Gradle
Issue I am trying to implement a custom accessor naming strategy like documented here: http://mapstruct.org/documentation/stable/reference/html/#using-spi However, I can’t get it to work with Gradle. There only seems to be a usage example for Maven: https://github.com/mapstruct/mapstruct-examples/tree/master/mapstruct-spi-accessor-naming Has anyone even tried using
Continue readingHow to map JAXB elements annotated with @XMLSeeAlso using mapStruct?
Issue I’m trying to map a bean which has some JAXB elements like @XmlSeeAlso, @XmlElement, @XmlSchemaType as properties for that class. @XmlAccessorType(XmlAccessType.FIELD) @XmlType(name = “Customer”) @XmlSeeAlso({PersonalCustomer.class, BusinessCustomer.class}) public class Customer extends Role { @XmlElement(name = “AMLLineOfBusiness”) private LOB amlLineOfBusiness; //
Continue readingNested Mapping using MapStruct
Issue class Identifier { private long id; private String type; private List<Status> statuses; } class Customer { private Identifier identifier; } class CustomerProfile { private Customer customer; } class CustomerIdentifierDO { private long id; } class CustomeDO { private CustomerIdentiferDO
Continue readingModelMapper: mapping abstract classes during runtime
Issue I am using ModelMapper Framework (http://modelmapper.org/) for mapping objects in Java. I have encountered a problem while mapping concrete classes (DTO to Entites) containing abstract classes. Example: Task has a list of AbstractItems. AbstractItems are Question and Criteria. public
Continue readingMap Nested elements – Mapstruct
Issue I’m trying to map following source classes to target class using MapStruct. Target Classes : public class Response { private List<Customer> customer = new ArrayList<Customer>(); } public class Customer { private String customerId; private List<Product> products = new ArrayList<Product>();
Continue readingMultiple problems regarding MapStruct mapping
Issue I am new to using MapStruct and thus facing some issues with the same. I have the following Model classes :- @Data class User { @Field private String fullName; @Field(“experience”) private List<Experience> workExperience; //other fields } @Data class Experience
Continue readingConfiguring ObjectMapper in Spring
Issue my goal is to configure the objectMapper in the way that it only serialises element which are annotated with @JsonProperty. In order to do so I followed this explanation which says how to configurate the objectmapper. I included the
Continue readingMapStruct: Map multiple sources from multiple objects to one target
Issue I want to map the following classes class Schedule { ZoneId timezoneId; List<AvailabilityRule> rules; } class AvailabilityRule { long startEpoch; long endEpoch; } to these classes. class ScheduleDTO { String timezone; List<AvailabilityRuleDTO> rules; } class AvailabilityRuleDTO { ZonedDateTime startTime;
Continue readingMapstruct Mapping : Return null object if all source parameters properties are null
Issue I want the generated mapstruct mapping method to return null if all the properties referenced in @Mapping/source are null. For exemple, I have the following mapping : @Mappings({ @Mapping(target = “id”, source = “tagRecord.tagId”), @Mapping(target = “label”, source =
Continue readingLinkedList insert tied to inserted object
Issue I have code that looks like this: public class Polynomial { List<Term> term = new LinkedList<Term>(); and it seems that whenever I do something like term.add(anotherTerm), with anotherTerm being… another Term object, it seems anotherTerm is referencing the same
Continue readingWhich is faster: Cloning or using Streams?
Issue In Java, which is faster: Cloning an Object, then passing it to multiple listeners assuming the cloned object contains nothing more complicated than nested arrays, primitives and Strings Using Streams to pass data through from one object to another?
Continue readingImplementing clone on a LinkedList
Issue I am trying to implement a clone() method on a DoubleLinkedList. Now, the problem is that implementing it by “the convention” is a lot more troublesome than just creating a new DoubleLinkedList and filling it with all the elements
Continue readingHow to clone an Object you dont know the type of?
Issue its easier to explain in code so here Object anObj; anObj = new MyObj(); anObj = new Rectangle(); anObj.clone();//this doesnt exist because its on the root Object class what can i use instead of the Object.clone() method in this
Continue readingUnable to understand clone
Issue I have a simple program to clone a object , I googled the error “Exception in thread “main” java.lang.CloneNotSupportedException:” but need your help to understand the error, why am I not able to get clone of obj1? public class
Continue readingCopying objects in java
Issue I want to perform a deep copy on an object, does the clone function work to that extent, or do I have to create a function to physically copy it, and return a pointer to it? That is, I
Continue readingHow to avoid instanceof in copy constructor for inherited java clasess
Issue I am writing a copy constructor for cloning an object. When a class has a refernce to an object which is further inhertited by few other classes. class Person { String name; Address address; } class HomeAdress extends Address
Continue readingHow to clone a multidimensional array in java?
Issue Edit 2: Below is a code snippet based on DuffyMo’s response that illustrates how to get around the limitations of cloning for multidimensional arrays using System.arraycopy. import java.util.Arrays; public class Randar { public static int[][] arrayMaster = {{6,1}, {10,1},
Continue readingHow to find difference between cloned object and orignal object in java?
Issue I am doing deep cloning. I am not considering some components of objects while cloning since it’s contains lot of elements. Now there is some code which uses that object , my code is failing because it needs some
Continue readingCloning and serializing a final object
Issue When a class is declared as final, is it possible to clone or serialize it’s objects? Or is this impossible because final prevents the extending of subclasses, therefore preventing cloning and serialization from implemented? Solution Final for classes –>
Continue readingAbout new objects
Issue I have a base object in a game that is used for stats. I copy the object each time I start a battle for the 40 sum units on the battle map. I then modify the stats object for
Continue readingJava return copy to hide future changes
Issue In Java, say you have a class that wraps an ArrayList (or any collection) of objects. How would you return one of those objects such that the caller will not see any future changes to the object made in
Continue readingSpring: Create new instance of bean for each call of get method
Issue I have next situation: Connection manager should have each time one object of ConnectionServer and new objects of DataBean So, I have created these beans and configured out it spring xml. <?xml version=”1.0″ encoding=”UTF-8″?> <beans xmlns=”http://www.springframework.org/schema/beans” xmlns:xsi=”http://www.w3.org/2001/XMLSchema-instance” xmlns:context=”http://www.springframework.org/schema/context” xsi:schemaLocation=”http://www.springframework.org/schema/beans
Continue readingShallow cloning in java : String and Object showing different behaviours
Issue Questions are based on the following code : class Car implements Cloneable { //Relevant constructor String name; int wheels; Car another; public Object clone() { /*DEEP Car n = new Car(this.name,this.wheels); n.another = new Car(this.another.name,this.another.wheels); return n; */ return
Continue readingSpecific use case for Dozer bean-to-bean mapping?
Issue I am tyring to understand, fundamentally, what problem(s) the Dozer Mapping framework solves. According to their tutorials, Dozer: Dozer is a Java Bean to Java Bean mapper that recursively copies data from one object to another. Typically, these Java
Continue readingConfused about cloning in Java
Issue I have this code in Java. public class CloneTest implements Cloneable{ String name; int marks; public CloneTest(String s, int i) { name = s; marks = i; } public void setName(String s) { name = s; } public void
Continue readingJava – cloning through extending
Issue Imagine situation: I have got two classes public class Fruit{ } and: public class FruitOnSale extends Fruit{ int price; public int getPrice() or something } My program has one fruit and one fruitOnSale object. I would like to create
Continue readingJava cloning method does not work
Issue I am copying the the current best solution of my program as follows: public Object clone() { MySolution copy = (MySolution)super.clone(); copy.wtour = (int[])this.wtour.clone(); copy.w = (int[][][][])this.w.clone(); return copy; } When I request the overall best solution in the
Continue readingDeep Cloning of Collections in java
Issue Recently I faced this question in an Interview: Write a function to return a deep clone instance of class Drawing public class Drawing{ public List<Shape> shapes=new LinkedList<Shape>(); } where shape is an abstract class having many concrete implementations public
Continue readingWhy do we implement Cloneable even if we can go for deep cloning using the following snippet
Issue public class Color { String color; Color(String color) { this.color=color; } } public class ColoredCircle { int x; Color color; ColoredCircle(int x, Color color) { this.x=x; this.color=color; } public Object testClone() { Color c = new Color(this.color.color); ColoredCircle cc1
Continue readingCloning in Java object that got in attribute the same object
Issue I’ve read this subject : http://howtodoinjava.com/2012/11/08/a-guide-to-object-cloning-in-java/. I’ve done a few test and it works. Now, my problem is cloning an object A that got a list of others objects A. For example : public class Cell { Cell[] listOfCells;
Continue readingJava: Create Instances based on prototype
Issue How can I, and What is the best/proper way (ie, most performant and clearest syntactically) in Java to create object instances based on a prototype object instance, when this will occur repeatedly and in a performance critical code path?
Continue readingEfficient way to clone a generic object in Java preferably without a factory
Issue I find my self having to export references to keys in an underlying Java collections map. I don’t want to give out references to the actual key objects but copies of them to ensure that nobody fiddles with the
Continue readingHow is cloning different from just assigning values (why bother implementing interface Cloneable)?
Issue im trying to create a deep copy of a class. Here is the class im trying to copy and the last method is the copy one: import java.util.ArrayList; import java.util.List; public class catalog implements Cloneable{ List<product> cat = new
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