Lately a friend asked me why there's no such thing as the clone function in C#. But I don't really get why to use clone except of this:
SomeClass cls = new SomeClass();
SomeClass cls2 = cls;
Why would you use = cls.clone();, so like this:
SomeClass cls = new SomeClass();
SomeClass cls2 = (SomeClass) cls.clone();
I never understood the difference. Can anyone explain which one is better and what the difference is?
What you have done here
SomeClass cls = new SomeClass();
SomeClass cls2 = cls;
Was creating TWO referencec to ONE, same object. Picture (may be a bit ugly because I drew it myself ;)):
In this code however:
SomeClass cls = new SomeClass();
SomeClass cls2 = (SomeClass) cls.clone();
You created TWO Objects with TWO references, where the second object is a copy of the first object. cls points to the first object, whilst cls2 points to the second one. Jvm will have to reserve space for two different objects instead of just one. Picture:
InputMismatchException - if the next token does not match the Integer regular expression, or is out of range. Integer.MIN_VALUE: -2147483648 Integer.MAX_VALUE: 2147483647 Instead of int use long long z = sc.nextLong(); ...
java,asynchronous,akka,blocking,future
If I understand this correctly, you kind of have two options here: you listen to a Future being completed or you do something with the result: If you want to listen, you can use some callback like final ExecutionContext ec = system.dispatcher(); future.onSuccess(new OnSuccess<String>() { public void onSuccess(String result) {...
java,spring,logging,lightadmin
You can use the class AbstractRepositoryEventListener like it's show on the LightAdmin documentation here Add you logger insertion by overiding onAfterSave, onAfterCreate and onAfterDelete into your own RepositoryEventListener. After you just need to register your listener like this public class YourAdministration extends AdministrationConfiguration<YourObject> { public EntityMetadataConfigurationUnit configuration(EntityMetadataConfigurationUnitBuilder configurationBuilder) { return...
On the link you post, I see a class like below. Create this class in your project before using it. private class AsyncCallWS extends AsyncTask<String, Void, Void> { @Override protected Void doInBackground(String... params) { Log.i(TAG, "doInBackground"); getFahrenheit(celcius); return null; } @Override protected void onPostExecute(Void result) { Log.i(TAG, "onPostExecute"); tv.setText(fahren +...
You should not let BehaviourItem implement Comparable as it doesn’t have a natural order. Instead, implement different Comparators for the different properties. Note that in Java 8, you can implement such a Comparator simply as Comparator<BehaviourItem> orderBySpeed=Comparator.comparingInt(BehaviourItem::getSpeed); which is the equivalent of Comparator<BehaviourItem> orderBySpeed=new Comparator<BehaviourItem>() { public int compare(BehaviourItem a, BehaviourItem...
java,selenium,webdriver,junit4
Your ID is dynamic, so you can't use it. Select will not work in your case, you just need to use two clicks WebElement dropdown = driver.findElement(By.xpath("//div[@class='select-pad-wrapper AttributePlugin']/input")); dropdown.click(); WebElement element = driver.findElement(By.xpath("//div[@class='select-pad-wrapper AttributePlugin']/div/ul/li[text()='Image']")); element.click(); ...
You shouldn't use constant a pixel-to-unit conversion, as this would lead to different behavior on different screen sizes/resolutions. Also don't forget about different aspect ratios, you also need to take care about them. The way you should solve this problem is using Viewports. Some of them support virtual screen sizes,...
It Should be a loop inside loop for column and row final Table<String, String, List<String>> values = HashBasedTable.create(); values.put("ton bon", "currency", Lists.newArrayList("ccdd","rode1","cwey","Certy")); values.put("ton bon", "racy", Lists.newArrayList("wqadd","werde","ihtr","ytre")); Map<String, List<String>> row = values.row("ton bon"); Map<String, String> fmap = new HashMap<String, String>(); System.out.println("Key\tValue"); for(String columnKey:row.keySet()) { List<String> rowValues =...
Columns don't contain items, Rows contain items. You can set the visible columns by passing a array to the setVisibleColumns methos of the Table. It could also be a idea, to just colapse the column, not hiding it... Determining if all values of this colum are empty should be simple...
java,mysql,hibernate,java-ee,struts2
You can simply create an Entity, that's mapping the database view: @Entity public class CustInfo { private String custMobile; private String profession; private String companyName; private Double annualIncome; } Make sure you include an @Id in your view as well, if that's an updatable view. Then you can simply use...
The indexOf method doesn't accept a regex pattern. Instead you could do a method like this: public static int indexOfPattern(List<String> list, String regex) { Pattern pattern = Pattern.compile(regex); for (int i = 0; i < list.size(); i++) { String s = list.get(i); if (s != null && pattern.matcher(s).matches()) { return...
The issue is with the dependencies that you have in pom.xml file. In Spring 4.1.* version the pom.xml dependency for Jackson libraries should include these: <dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-core</artifactId> <version>2.4.1</version> </dependency> <dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-databind</artifactId> <version>2.4.1.1</version> </dependency> You...
In Java, you cannot write executable statements directly in class.So this is syntactically wrong: for(int i=0; i<10; i++) { this.colorList[i] = this.allColors[this.r.nextInt(this.allColors.length)]; } Executable statements can only be in methods/constructors/code blocks...
else { System.out.println(diceNumber); } You are printing the address of diceNumber by invoking its default toString() function in your else clause. That is why you are getting the [email protected] The more critical issue is why it gets to the 'else' clause, I believe that is not your intention. Note: In...
In your MainActivity.java at line no 34 you are trying to initialize some widget that is not present in your xml layout which you have set it in your setContentView(R.layout.... That;s why you are geting nullpointerexception. EDIT: change your setContentView(R.layout.activity_main) to setContentView(R.layout.fragment_main)...
You try to cast data type mx.collections:IList to UI component type spark.components:List, which of course leads to exception. Try to follow the error message hint and use mx.collections:IList: screenList.addAll(event.result as IList); ...
No, there's no need, the JavaDoc tool parses the Java code and gets the types from there. This article on the Oracle Java site may be useful: How to Write Doc Comments for the Javadoc Tool From the @param part of that article: The @param tag is followed by the...
java,android,listview,android-fragments,expandablelistview
You shouldn't pass your view item form a fragment to an other. You should retrieve the object associated with your group view, pass this object to your second/edition fragment. You can use setTargetFragment(...) and onActivityResult(...) to send the modified text from your second to your first fragment. And then you...
java,while-loop,java.util.scanner
You are reading too much from the scanner! In this line while (sc.nextLine() == "" || sc.nextLine().isEmpty()) you are basically reading a line from the scanner, comparing it (*) with "", then forgetting it, because you read the next line again. So if the first read line really contains the...
After the API 1.5.6 we have a different way to get the String bound. try this GlyphLayout layout = new GlyphLayout(); layout.setText(bitmapFont,"text"); float width = layout.width; float height = layout.height; and it's not recommended to create new GlyphLayout on each frame, create once and use it. ...
java,list,collections,listiterator
You're reading the wrong documentation: you should read ListIterator's javadoc. It says: Throws: ... IllegalStateException - if neither next nor previous have been called, or remove or add have been called after the last call to next or previous Now, if you want a reason, it's rather simple. You're playing...
I wrote a quick method for you that I think does what you want, i.e. remove all occurrences of a token in a line, where that token is embedded in the line and is identified by a leading dash. The method reads the file and writes it straight out to...
java,android,gps,geolocation,location
See my post at http://gabesechansoftware.com/location-tracking/. The code you're using is just broken. It should never be used. The behavior you're seeing is one of the bugs- it doesn't handle the case of getLastLocation returning null, an expected failure. It was written by someone who kind of knew what he was...
It's not possible to do this using only the ArrayList. Either implement your own method which can be as simple as: private List<mystatistik> getAllUniqueEnemies(List<mystatistik> list){ List<mystatistik> uniqueList = new ArrayList<mystatistik>(); List<String> enemyIds = new ArrayList<String>(); for (mystatistik entry : list){ if (!enemyIds.contains(entry.getEnemyId())){ enemyIds.add(entry.getEnemyId()); uniqueList.add(entry); } } return uniqueList; } Or...
-0777 is treated by the compiler as an octal number (base 8) whose decimal value is -511 (-(64*7+8*7+7)). -777 is a decimal number.
The name of your getter & setter is wrong. By convention it must be: public Integer getSurvey_id() { return survey_id; } public void setSurvey_id(Integer survey_id) { this.survey_id=survey_id; } ...
If you can identify the thread you want to "mute" reliably somehow (e.g. by name), you can setOut to your own stream which will only delegate the calls to the actual System.out if they don't come from the muted thread.
Instead of using driver.quit() to close the browser, closing it using the Actions object may work for you. This is another way to close the browser using the keyboard shortcuts. Actions act = new Actions(driver); act.sendKeys(Keys.chord(Keys.CONTROL+"w")).perform(); Or, if there are multiple tabs opened in driver window: act.sendKeys(Keys.chord(Keys.CONTROL,Keys.SHIFT+"w")).perform(); ...
java,android,eclipse,sdk,versions
There shouldn't be any problem if you use the latest SDK version ; actually, this is recommended. However, make sure to set the correct "Target SDK", i.e. the highest android version you have successfully tested your app with, and the "Minimum Required SDK" as well....
java,jsp,spring-mvc,liferay,portlet
Which version of Liferay you are using? if it is > 6.2 GA1 Then in your liferay-portlet.xml file, please add this attribute and recompile and test again. <requires-namespaced-parameters>false</requires-namespaced-parameters> Liferay adds namespace to the request parameters by default. You need to disable it. ...
java,android,android-intent,uri,avd
Change your onClick method to below code. You should give the option to choose the external player. @Override public void onClick(View v) { Intent intent = new Intent(Intent.ACTION_VIEW); intent.setDataAndType(Uri.parse("https://youtu.be/jxoG_Y6dvU8"), "video/*"); startActivity(Intent.createChooser(intent, "Complete action using")); } ...
java,android,android-fragments,spannablestring
If LoginActivity is a fragment class then it would be okay is you use setOnClickListener on textview. But for fragment change you have to change Intent to fragmentTransaction, Use something like, textview.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { getFragmentManager().beginTransaction().replace(R.id.container, new LoginActivity() ).addToBackStack("").commit(); }); But, if you want to...
deleteEmployee method is not wrapped into a new transaction because you are referencing method on this. What you can do is to inject reference to the facade itself and then call deleteEmployee method on it (it should be public). More or less something like this: @Stateless public class MyFacade {...
Say you have a jsp test.jsp under /WEB-INF/jsp/reports From your controller return @RequestMapping("/helloWorld") public String helloWorld(Model model) { model.addAttribute("message", "Hello World!"); return "reports/test"; } ...
Actually you can generate class with soap ui. And your program can easily call the service using the class created without construct your own request header and body But you need some library. Example java jdk comes with jax-ws lib tutorial: http://www.soapui.org/soap-and-wsdl/soap-code-generation.html...
The 000000b0 is not part of the data. It's the memory address where the following 16 bytes are located. The two-digit hex numbers are the actual data. Read them from left to right. Each row is in two groups of eight, purely to asist in working out memory addresses etc....
There won't be any difference, since you've only changed the scope of the variables. Since you're not using the variables outside of the scope, the generated bytecode will be identical as well (you can try it out with javap). So use the second style for clarity. Edit: In fact if...
Use {} instead of () because {} are not used in XPath expressions and therefore you will not have confusions.
Use URLConnection.setUseCaches(boolean);. In your case, it would be connection.setUseCaches(false);...
No, we cannot by definition. The IP address is needed to hide the mac address from external world. To retrieve it you definitely need some code running on that machine. It means that you need some kind of agent. You can either implement it in Java or use platform specific...
java,apache-spark,apache-spark-sql
If you use plain spark you can join two RDDs. let a = RDD<Tuple2<K,T>> let b = RDD<Tuple2<K,S>> RDD<Tuple2<K,Tuple2<S,T>>> c = a.join(b) This produces an RDD of every pair for key K. There are also leftOuterJoin, rightOuterJoin, and fullOuterJoin methods on RDD. So you have to map both datasets to...
java,elasticsearch,elasticsearch-plugin
When indexing documents in this form, Elasticsearch will not be able to parse those strings as dates correctly. In case you transformed those strings to correctly formatted timestamps, the only way you could perform the query you propose is to index those documents in this format { "start": "2010-09", "end":...
You can do it with rJava package. install.packages('rJava') library(rJava) .jinit() jObj=.jnew("JClass") result=.jcall(jObj,"[D","method1") Here, JClass is a Java class that should be in your ClassPath environment variable, method1 is a static method of JClass that returns double[], [D is a JNI notation for a double array. See that blog entry for...
Correct me if I'm wrong. If you're saying that your code looks like this: new Thread(new Runnable() { public void run() { // thread code if (ready.equals("yes")) { // handler code } // more thread code }).start(); // later on... ready = "yes"; And you're asking why ready = "yes"...
I recommend you to use DeferredResult of Spring. It´s a Future implementation, that use the http long poling technique. http://docs.spring.io/spring-framework/docs/3.2.0.BUILD-SNAPSHOT/api/org/springframework/web/context/request/async/DeferredResult.html So let´s says that you will make a request, and the server it will return you the deferredResult, and then your request will keep it open until the internal process(Hibernate)...
I'm sad that this question hasn't been answered, and upon that, I can't upvote it from it's -8 cause I don't have enough reputation. It seems downvoting is getting too unwarranted here. OP is just looking for an answer, which can be answered here and found online, he has tried...
After super.onCreate(savedInstanceState); insert setContentView(R.layout.YourLayout); you need to make a request to a server in another thread. It might look like public class LoginTask extends AsyncTask<Void, Void, String>{ private String username; private String password; private Context context; public LoginTask(Context context, String username, String password) { this.username = username; this.password = password;...
You may try this query: select stop_name from behaviour where created_at in (select max(created_at) from behaviour) ...
Math.floor(x+0.7) should do it. This should work for an arbitrary mantissa. Just add the offset to the next integer to your value and round down. The rounding is done by floor. Here is what the java API says to floor: Returns the largest (closest to positive infinity) double value that...
An execution result is essentially an iterator of a map, its type definition is something like: Iterable<Map<String,Object>> So you can easily just do: result.iterator().hasNext(); I think that its strictly a ResourceIterator, so if you get an iterator you are supposed to close it if you don't exhaust it. Check the...