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  • Where will the image be saved? [closed]

    - by Dummy Derp
    import java.awt.Dimension; import java.awt.Rectangle; import java.awt.Robot; import java.awt.Toolkit; import java.awt.image.BufferedImage; import javax.imageio.ImageIO; import java.io.File; ... public void captureScreen(String fileName) throws Exception { Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize(); Rectangle screenRectangle = new Rectangle(screenSize); Robot robot = new Robot(); BufferedImage image = robot.createScreenCapture(screenRectangle); ImageIO.write(image, "png", new File(fileName)); } ... Going over this code I found on the internet. I got everything except the part where file is created. In what format file name should be? Should it be C:/myFolder/myImage.png" or just myImage.png and where will it be saved? Here is what docs say: File public File(String pathname) Creates a new File instance by converting the given pathname string into an abstract pathname. If the given string is the empty string, then the result is the empty abstract pathname. Parameters: pathname - A pathname string Throws: NullPointerException - If the pathname argument is null

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  • What's your advice for getting Oracle Certified Professional Java Programmer certificate?

    - by den-javamaniac
    Hi. I intend to get the certification but am not completely sure how to effectively prepare myself. So I'm wondering if you have any advice on the matter; in particular I would like to know: - What should the basic learning/practicing plan look like? - Which book (set of books) should be considered? - Which practical exercises should be performed? NOTE: I've got several years of corporate experience (mostly web apps, though), but I want to be 100% sure I'll pass the test (that's the reason the issue is raised).

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  • Are there any good Java/JVM libraries for my Expression Tree architecture?

    - by Snuggy
    My team and I are developing an enterprise-level application and I have devised an architecture for it that's best described as an "Expression Tree". The basic idea is that the leaf nodes of the tree are very simple expressions (perhaps simple values or strings). Nodes closer to the trunk will get more and more complex, taking the simpler nodes as their inputs and returning more complex results for their parents. Looking at it the other way, the application performs some task, and for this it creates a root expression. The root expression divides its input into smaller units and creates child expressions, which when evaluated it can use to build it's own result. The subdividing process continues until the simplest leaf nodes. There are two very important aspects of this architecture: It must be possible to manipulate nodes of the tree after it is built. The nodes may be given new input values to work with and any change in result for that node needs to be propagated back up the tree to the root node. The application must make best use of available processors and ultimately be scalable to other computers in a grid or in the cloud. Nodes in the tree will often be updating concurrently and notifying other interested nodes in the tree when they get a new value. Unfortunately, I'm not at liberty to discuss my actual application, but to aid understanding a little bit, you might imagine a kind of spreadsheet application being implemented with a similar architecture, where changes to cells in the table are propagated all over the place to other cells that need the result. The spreadsheet could get so massive that applying multi-core multi-computer distributed system to solve it would be of benefit. I've got my prototype "Expression Engine" working nicely on a single multi-core PC but I've started to run into a few concurrency issues (as expected because I haven't been taking too much care so far) so it's now time to start thinking about migrating the Engine to a more robust library, and that leads to a number of related questions: Is there any precedent for my "Expression Tree" architecture that I could research? What programming concepts should I consider. I realise this approach has many similarities to a functional programming style, and I'm already aware of the concepts of using futures and actors. Are there any others? Are there any languages or libraries that I should study? This question is inspired by my accidental discovery of Scala and the Akka library (which has good support for Actors, Futures, Distributed workloads etc.) and I'm wondering if there is anything else I should be looking at as well?

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  • What's your advice in getting Oracle Certified Professional Java Programmer certificate?

    - by den-javamaniac
    Hi. I'm intending to get the certification but not completely sure how to time effectively prepare myself. So I'm wondering if I can be advised on the matter, in particular I would like next questions to be answered: - What the basic learning/practicing plan should look like? - What book (set of books) should be considered? - What practical exercises should be performed? NOTE: I've got several years of corporate experience (mostly web apps, though), but I want to be 100% sure I'll pass the test (that's the reason the issue is raised).

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  • Work @ Java shop. Tasked to redo intranet. I only know PHP - CTO says use that; Ops Says no - we have JSP, use that - Thoughts?

    - by Mackysback
    So I work as a project manager and was given the opportunity to redo the intranet and Internet site... I'd love to , great addition to my resume. However.... I am not familiar with java nor JSP... I am fairly proficient with PHP and MySQL ... Also my intention was to use a CMS that I have experience with, wordpress, drupal or joomla... The site would be very simple so I was thinking wordpress would be fine for this. I told management that I would need it to run on PHP and they gave me their blessing... Now the disconnect bw it and management ... I spoke with ops and they told me that we have java and JSP for that purpose although the IT guy did say "oh but I do know that php and mysql are gaining popularity" That said ... I do not understand much as far as systems architecture... We do self host and run websphere with IIS and jboss with tomcat. Any advice or suggestions? Thanks ! Is my request that unfeasible?

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  • Java EE/GlassFish@Java2Days

    - by reza_rahman
    Java2Days 2012 was held in Sofia, Bulgaria on October 25-26. This was the third installment of the premier Java conference for the Balkan region, having three separate tracks for Java, the Cloud and Mobile. It attracted over a thousand enthusiastic, bright young developers and a number of world class speakers. There were no less than three full-house sessions on Java EE/GlassFish - one on Java EE 7, one on Domain-Driven Design using Java EE 6 and one on JSR 356/WebSocket. More details on Java EE/GlassFish@Java2Days, including slides and code examples, posted here.

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  • Have I mistakenly assumed that my routines are loosely coupled?

    - by Tarun
    My Selenium test structures goes as - Data Object class - public class RegistrationData { String firstName = "test first name"; String lastName = "test last name"; // Getter Setter Here } Page Object class which carries out operations on a Web Page - public class RegistrationPage { private RegistrationData regData; public void setRegistrationData(RegistrationData regData) { this.regData = regData(); public NewAccountPage fillRegForm() { enterFirstName("FirstNameTextBoxLocator", regData.getFirstName); enterLastName("LastNameTextBoxLocator", regData.getLastName); // Some more fields are filled here return NewAccountPage(); } } And test class uses them as - public class TestRegistration extends SelTestCase { @Test public void testRegNewUser() { RegistrationData regData = new RegistrationData(); RegistrationPage regPage = New RegistrationPage(); regPage.setRegistrationData(regData) regPage.fillRegForm(); // Some assertion here } } Now since fillRegForm method does not take any argument, Can I assume that it is an example of loose coupling despite I need to set RegistrationData in RegistrationPage before being able to use fillRegForm method.

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  • What Java data structure/design pattern best models this object, considering it would perform these methods?

    - by zundarz
    Methods: 1. getDistance(CityA,CityB) // Returns distance between two cities 2. getCitiesInRadius(CityA,integer) // Returns cities within a given distance of another city 3. getCitiesBeyondRadius(CityA,integer) //Returns cities beyond a given distance of another city 4. getRemoteDestinations(integer) // Returns all city pairs greater than x distance of each other 5. getLocalDestinations(integer) //Returns all city pairs within x distance of each other

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  • How can I improve these online java programming puzzles I wrote for my (middle/high school) students?

    - by Arcymag
    I'm teaching some middle and high school students programming right now, and I found that some of them really liked online programming puzzles. So I created http://www.kapparate.com/coder/ , and right now there's 4 categories of puzzles. All the puzzles are set up right now so that variables are pre-initialized, and the user plugs in some code in the middle. For example, the problem might say these are pre-initialized: int x = ????; int y = ????; int z; and then the program might ask the student to write the final line of code: z = x + y;. Now I know I could go a long way in improving the usability of this site (like having an area that lists the pre-defined variables), but I was wondering if this concept seems sound. I know some sites have kids fill in functions, but not all of my students know what functions are yet, and I'm trying to introduce online programming puzzles before that.

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  • Java Substance look and feel problem

    - by 2xMax
    I have a problem with substance look and feel. I'm trying to set Office 2007 LAF as descibed here. try { UIManager.setLookAndFeel("org.pushingpixels.substance.api.skin.SubstanceOfficeBlue2007LookAndFeel"); }catch(Exception ex) { System.out.println("Exception:"+ ex.getMessage()); } But when i run this code I get exception: Exception in thread "main" java.lang.NoClassDefFoundError: org/pushingpixels/trident/ease/TimelineEase What am I doing wrong? Anybody have experience with substance LAF?

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  • android database leak found IllegalStateException

    - by saravanan
    04-20 16:53:39.010: ERROR/Database(419): Leak found 04-20 16:53:39.010: ERROR/Database(419): java.lang.IllegalStateException: mPrograms size 1 04-20 16:53:39.010: ERROR/Database(419): at android.database.sqlite.SQLiteDatabase.finalize(SQLiteDatabase.java:1668) 04-20 16:53:39.010: ERROR/Database(419): at dalvik.system.NativeStart.run(Native Method) 04-20 16:53:39.010: ERROR/Database(419): Caused by: java.lang.IllegalStateException: /data/data/com.example.search/databases/rlite.db SQLiteDatabase created and never closed 04-20 16:53:39.010: ERROR/Database(419): at android.database.sqlite.SQLiteDatabase.(SQLiteDatabase.java:1694) 04-20 16:53:39.010: ERROR/Database(419): at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:738) 04-20 16:53:39.010: ERROR/Database(419): at android.database.sqlite.SQLiteDatabase.openOrCreateDatabase(SQLiteDatabase.java:760) 04-20 16:53:39.010: ERROR/Database(419): at android.database.sqlite.SQLiteDatabase.openOrCreateDatabase(SQLiteDatabase.java:753) 04-20 16:53:39.010: ERROR/Database(419): at android.app.ApplicationContext.openOrCreateDatabase(ApplicationContext.java:473) 04-20 16:53:39.010: ERROR/Database(419): at android.content.ContextWrapper.openOrCreateDatabase(ContextWrapper.java:193) 04-20 16:53:39.010: ERROR/Database(419): at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:98) 04-20 16:53:39.010: ERROR/Database(419): at com.example.search.Database.(Database.java:33) 04-20 16:53:39.010: ERROR/Database(419): at com.example.search.JobDetails.applyJob(JobDetails.java:120) 04-20 16:53:39.010: ERROR/Database(419): at com.example.search.JobDetails.jobdetailsAction(JobDetails.java:98) 04-20 16:53:39.010: ERROR/Database(419): at java.lang.reflect.Method.invokeNative(Native Method) 04-20 16:53:39.010: ERROR/Database(419): at java.lang.reflect.Method.invoke(Method.java:521) 04-20 16:53:39.010: ERROR/Database(419): at android.view.View$1.onClick(View.java:2026) 04-20 16:53:39.010: ERROR/Database(419): at android.view.View.performClick(View.java:2364) 04-20 16:53:39.010: ERROR/Database(419): at android.view.View.onTouchEvent(View.java:4179) 04-20 16:53:39.010: ERROR/Database(419): at android.widget.TextView.onTouchEvent(TextView.java:6540) 04-20 16:53:39.010: ERROR/Database(419): at android.view.View.dispatchTouchEvent(View.java:3709) 04-20 16:53:39.010: ERROR/Database(419): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884) 04-20 16:53:39.010: ERROR/Database(419): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884) 04-20 16:53:39.010: ERROR/Database(419): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884) 04-20 16:53:39.010: ERROR/Database(419): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884) 04-20 16:53:39.010: ERROR/Database(419): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884) 04-20 16:53:39.010: ERROR/Database(419): at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:1659) 04-20 16:53:39.010: ERROR/Database(419): at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1107) 04-20 16:53:39.010: ERROR/Database(419): at android.app.Activity.dispatchTouchEvent(Activity.java:2061) 04-20 16:53:39.010: ERROR/Database(419): at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1643) 04-20 16:53:39.010: ERROR/Database(419): at android.view.ViewRoot.handleMessage(ViewRoot.java:1691) 04-20 16:53:39.010: ERROR/Database(419): at android.os.Handler.dispatchMessage(Handler.java:99) 04-20 16:53:39.010: ERROR/Database(419): at android.os.Looper.loop(Looper.java:123) 04-20 16:53:39.010: ERROR/Database(419): at android.app.ActivityThread.main(ActivityThread.java:4363) 04-20 16:53:39.010: ERROR/Database(419): at java.lang.reflect.Method.invokeNative(Native Method) 04-20 16:53:39.010: ERROR/Database(419): at java.lang.reflect.Method.invoke(Method.java:521) 04-20 16:53:39.010: ERROR/Database(419): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860) 04-20 16:53:39.010: ERROR/Database(419): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618) 04-20 16:53:39.010: ERROR/Database(419): at dalvik.system.NativeStart.main(Native Method) when i read the database show error like this. please do reply me

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  • Java OutOfMemory error in filter

    - by The Machine
    I get a java.lang.outOfMemoryError exception, while writing a big file to the servletOutputStream. Every response is by default wrapped using a ehcache.constructs.web.filter Object for GZIP compression. And as per the logs, the exception is thrown in the Filter object. Is there a way to increase the available memory so, that the outOfMemoryError Exception does not occur ?

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  • Android: Custom ListAdapter extending BaseAdapter crashes on application launch.

    - by Danny
    Data being pulled from a local DB, then mapped using a cursor. Custom Adapter displays data similar to a ListView. As items are added/deleted from the DB, the adapter is supposed to refresh. The solution attempted below crashes the application at launch. Any suggestions? Thanks in advance, -D @Override public View getView(int position, View convertView, ViewGroup parent) { View v = convertView; ViewGroup p = parent; if (v == null) { LayoutInflater vi = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE); v = vi.inflate(R.layout.items_row, p); } int size = mAdapter.getCount(); Log.d(TAG, "position " + position + " Size " + size); if(size != 0){ if(position < size) return mAdapter.getView(position, v, p); Log.d(TAG, "-position " + position + " Size " + size); } return null; } Errors: 03-23 00:14:10.392: ERROR/AndroidRuntime(718): java.lang.UnsupportedOperationException: addView(View, LayoutParams) is not supported in AdapterView 03-23 00:14:10.392: ERROR/AndroidRuntime(718): at android.widget.AdapterView.addView(AdapterView.java:461) 03-23 00:14:10.392: ERROR/AndroidRuntime(718): at android.view.LayoutInflater.inflate(LayoutInflater.java:415) 03-23 00:14:10.392: ERROR/AndroidRuntime(718): at android.view.LayoutInflater.inflate(LayoutInflater.java:320) 03-23 00:14:10.392: ERROR/AndroidRuntime(718): at android.view.LayoutInflater.inflate(LayoutInflater.java:276) 03-23 00:14:10.392: ERROR/AndroidRuntime(718): at com.xyz.abc.CustomSeparatedListAdapter.getView(CustomSeparatedListAdapter.java:90) 03-23 00:14:10.392: ERROR/AndroidRuntime(718): at android.widget.AbsListView.obtainView(AbsListView.java:1273) 03-23 00:14:10.392: ERROR/AndroidRuntime(718): at android.widget.ListView.makeAndAddView(ListView.java:1658) 03-23 00:14:10.392: ERROR/AndroidRuntime(718): at android.widget.ListView.fillDown(ListView.java:637) 03-23 00:14:10.392: ERROR/AndroidRuntime(718): at android.widget.ListView.fillFromTop(ListView.java:694) 03-23 00:14:10.392: ERROR/AndroidRuntime(718): at android.widget.ListView.layoutChildren(ListView.java:1516) 03-23 00:14:10.392: ERROR/AndroidRuntime(718): at android.widget.AbsListView.onLayout(AbsListView.java:1112) 03-23 00:14:10.392: ERROR/AndroidRuntime(718): at android.view.View.layout(View.java:6569) 03-23 00:14:10.392: ERROR/AndroidRuntime(718): at android.widget.FrameLayout.onLayout(FrameLayout.java:333) 03-23 00:14:10.392: ERROR/AndroidRuntime(718): at android.view.View.layout(View.java:6569) 03-23 00:14:10.392: ERROR/AndroidRuntime(718): at android.widget.FrameLayout.onLayout(FrameLayout.java:333) 03-23 00:14:10.392: ERROR/AndroidRuntime(718): at android.view.View.layout(View.java:6569) 03-23 00:14:10.392: ERROR/AndroidRuntime(718): at android.widget.FrameLayout.onLayout(FrameLayout.java:333) 03-23 00:14:10.392: ERROR/AndroidRuntime(718): at android.view.View.layout(View.java:6569) 03-23 00:14:10.392: ERROR/AndroidRuntime(718): at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1119) 03-23 00:14:10.392: ERROR/AndroidRuntime(718): at android.widget.LinearLayout.layoutVertical(LinearLayout.java:998) 03-23 00:14:10.392: ERROR/AndroidRuntime(718): at android.widget.LinearLayout.onLayout(LinearLayout.java:918) 03-23 00:14:10.392: ERROR/AndroidRuntime(718): at android.view.View.layout(View.java:6569) 03-23 00:14:10.392: ERROR/AndroidRuntime(718): at android.widget.FrameLayout.onLayout(FrameLayout.java:333) 03-23 00:14:10.392: ERROR/AndroidRuntime(718): at android.view.View.layout(View.java:6569) 03-23 00:14:10.392: ERROR/AndroidRuntime(718): at android.widget.FrameLayout.onLayout(FrameLayout.java:333) 03-23 00:14:10.392: ERROR/AndroidRuntime(718): at android.view.View.layout(View.java:6569) 03-23 00:14:10.392: ERROR/AndroidRuntime(718): at android.widget.FrameLayout.onLayout(FrameLayout.java:333) 03-23 00:14:10.392: ERROR/AndroidRuntime(718): at android.view.View.layout(View.java:6569) 03-23 00:14:10.392: ERROR/AndroidRuntime(718): at android.view.ViewRoot.performTraversals(ViewRoot.java:979) 03-23 00:14:10.392: ERROR/AndroidRuntime(718): at android.view.ViewRoot.handleMessage(ViewRoot.java:1613) 03-23 00:14:10.392: ERROR/AndroidRuntime(718): at android.os.Handler.dispatchMessage(Handler.java:99) 03-23 00:14:10.392: ERROR/AndroidRuntime(718): at android.os.Looper.loop(Looper.java:123) 03-23 00:14:10.392: ERROR/AndroidRuntime(718): at android.app.ActivityThread.main(ActivityThread.java:4203) 03-23 00:14:10.392: ERROR/AndroidRuntime(718): at java.lang.reflect.Method.invokeNative(Native Method) 03-23 00:14:10.392: ERROR/AndroidRuntime(718): at java.lang.reflect.Method.invoke(Method.java:521) 03-23 00:14:10.392: ERROR/AndroidRuntime(718): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:791) 03-23 00:14:10.392: ERROR/AndroidRuntime(718): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:549) 03-23 00:14:10.392: ERROR/AndroidRuntime(718): at dalvik.system.NativeStart.main(Native Method)

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  • Java Integer: what is faster comparison or subtraction?

    - by Vladimir
    I've found that java.lang.Integer implementation of compareTo method looks as follows: public int compareTo(Integer anotherInteger) { int thisVal = this.value; int anotherVal = anotherInteger.value; return (thisVal<anotherVal ? -1 : (thisVal==anotherVal ? 0 : 1)); } The question is why use comparison instead of subtraction: return thisVal - anotherVal;

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  • Critical tools that every Java Developer should have in his toolbelt?

    - by Timur Fanshteyn
    I was trying to compile a list of tools that a good Java Developer should be know of, and keep in his Developer Tool Belt I can think of a few Eclipse Development Environment - There are other IDEs, but you should know how Eclipse of eclipse. JUnit - Java Unit Testing Framework. Of course there are others, but... ANT Maven Soap UI - for testing SOAP endpoints jrat - Java Profiler. I don't know of other good Java profilers Java Decompiler - For when you just have to know what's in the jar file

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  • Wanted: a very simple java RegExp API

    - by itsadok
    I'm tired of writing Pattern p = Pattern.compile(... Matcher m = p.matcher(str); if (m.find()) { ... Over and over again in my code. I was going to write a helper class to make it neater, but I then I wondered: is there a library that tries to provide a simpler facade for Regular Expressions in Java? I'm thinking something in the style of commons-lang and Guava.

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  • How one extends JNA interface mappings? (Java)

    - by rukoche
    User32 interface (platform library) is missing some WinAPI functions, so I tried extending it: package myapp import com.sun.jna.platform.win32.W32API public interface User32 extends com.sun.jna.platform.win32.User32 { myapp.User32 INSTANCE boolean IsWindow(W32API.HWND hWnd) } But then calling myapp.User32.INSTANCE.FindWindow(..) results in java.lang.NullPointerException: Cannot invoke method FindWindow() on null object

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  • Java JList model

    - by Alaa
    How can I make a list model from a JList in order to be able to insert an item into it. I want to use this method: addElement(java.lang.Object item) I found an explanation here, but the problem is that ListModel is an interface and even if I write an implementation and override its method, I can't use the addElement() method

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  • java native Process timeout

    - by deltanovember
    At the moment I execute a native process using the following: java.lang.Process process = Runtime.getRuntime().exec(command); int returnCode = process.waitFor(); Suppose instead of waiting for the program to return I wish to terminate if a certain amount of time has elapsed. How do I do this?

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  • Java - when to use notify or notifyAll?

    - by mdma
    Why does java.lang.Object have two notify methods - notify and notifyAll? It seems that notifyAll does at least everything notify does, so why not just use notifyAll all the time? If notifyAll is used instead of notify, is the program still correct, and vice versa? What influences the choice between these two methods?

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  • Java Interger: what is faster comparison or subtraction?

    - by Vladimir
    I've found that java.lang.Ingteger implementation of compareTo method looks as follows: public int compareTo(Integer anotherInteger) { int thisVal = this.value; int anotherVal = anotherInteger.value; return (thisVal<anotherVal ? -1 : (thisVal==anotherVal ? 0 : 1)); } The question is why use comparison instead of subtraction: return thisVal - anotherVal;

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  • Converting String to int in Java and getting a NumberFormatException, can't figure out why

    - by user1687682
    ipString is a String representation of an IP address with spaces instead of dots. String[] ipArray = ipString.split(" "); String ip = ""; for (String part : ipArray){ if (part != null){ ip += part } } ip = ip.trim(); int ipInt = Integer.parseInt(ip); // Exception is thrown here. Exception in thread "main" java.lang.NumberFormatException: For input string: "6622015176". Could someone explain why this exception is being thrown?

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  • Why does limiting my virtual memory to 512MB with ulimit -v crash the JVM?

    - by Narinder Kumar
    I am trying to enforce maximum memory a program can consume on a Unix system. I thought ulimit -v should do the trick. Here is a sample Java program I have written for testing : import java.util.*; import java.io.*; public class EatMem { public static void main(String[] args) throws IOException, InterruptedException { System.out.println("Starting up..."); System.out.println("Allocating 128 MB of Memory"); List<byte[]> list = new LinkedList<byte[]>(); list.add(new byte[134217728]); //128 MB System.out.println("Done...."); } } By default, my ulimit settings are (output of ulimit -a) : core file size (blocks, -c) 0 data seg size (kbytes, -d) unlimited scheduling priority (-e) 0 file size (blocks, -f) unlimited pending signals (-i) 31398 max locked memory (kbytes, -l) 64 max memory size (kbytes, -m) unlimited open files (-n) 1024 pipe size (512 bytes, -p) 8 POSIX message queues (bytes, -q) 819200 real-time priority (-r) 0 stack size (kbytes, -s) 8192 cpu time (seconds, -t) unlimited max user processes (-u) 31398 virtual memory (kbytes, -v) unlimited file locks (-x) unlimited When I execute my java program (java EatMem), it executes without any problems. Now I try to limit max memory available to any program launched in the current shell to 512MB by launching the following command : ulimit -v 524288 ulimit -a output shows the limit to be set correctly (I suppose): core file size (blocks, -c) 0 data seg size (kbytes, -d) unlimited scheduling priority (-e) 0 file size (blocks, -f) unlimited pending signals (-i) 31398 max locked memory (kbytes, -l) 64 max memory size (kbytes, -m) unlimited open files (-n) 1024 pipe size (512 bytes, -p) 8 POSIX message queues (bytes, -q) 819200 real-time priority (-r) 0 stack size (kbytes, -s) 8192 cpu time (seconds, -t) unlimited max user processes (-u) 31398 virtual memory (kbytes, -v) 524288 file locks (-x) unlimited If I now try to execute my java program, it gives me the following error: Error occurred during initialization of VM Could not reserve enough space for object heap Could not create the Java virtual machine. Ideally it should not happen as my Java program is only taking around 128MB of memory which is well within my specified ulimit parameters. If I change the arguments to my Java program as below: java -Xmx256m EatMem The program again works fine. While trying to give more memory than limited by ulimit like : java -Xmx800m EatMem results in expected error. Why the program fails to execute in the first case after setting ulimit ? I have tried the above test on Ubuntu 11.10 and 12.0.4 with Java 1.6 and Java 7

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