float input to textfield and textarea java
Hi, i want to create text field and textarea which should only take float value as input how can i do this in java? ...
java
Setting a button
I have 2 buttons. One is "add". The other is "cancel". In the cancel button action, I want to write that until the add method is not called, this button do nothing. How can I do that? ...
What is an abstract class ?
When I learned about abstract classes is said WT(H*)!!! QUESTIONS: What is the point of creating a class that can't be instantiated? Why would anybody want such a class? What is the situation in which abstract classes become NECESSARY? *if you know what i mean ...
Why bother to write an iterator like this?
I was reading through the Java tutorial on inner class http://java.sun.com/docs/books/tutorial/java/javaOO/innerclasses.html It explains that in the example "The InnerEvenIterator inner class, which is similar to a standard Java iterator." So I take it that iterators are pretty common in Java? I came from a C programming background. I...
crawler get external website search result
What is the best practice and library I can use to key in search textbox on external website and collect the search result? How do tackle website with different search box and checkbox and collect the result? Can Selenium be used to automate this? Should I use Heritrix or nutch? Which one is better? I heard nutch comes with plugins. Whi...
What is causing the problem - I am not able launch JNLP aaplications using "Java Web Start" ?
Up until recently, I was able to launch/open JNLP files in Firefox using Java web start. Don't know what happened all of a sudden JNLP files stopped launching, a splash screen appears saying Java Starting... and then nothing happens. Even the Java Console in the browser and javacpl.cpl applet doesn't open. Tried all possibilities: remo...
AsyncTask and Contexts
So I'm working out my first multi-threaded application using Android with the AsyncTask class. I'm trying to use it to fire off a Geocoder in a second thread, then update the UI with onPostExecute, but I keep running into an issue with the proper Context. I kind of hobbled my way through using Contexts on the main thread, but I'm not ex...
How to add a popup menu to a JTextField
Can anybody explain me how to add a popup menu at a JtextField? I managed to add a JPopupMenu: JPopupMenu popup = new JPopupMenu(); popup.add("m"); popup.add("n"); JTextField textField = new JTextField(); textField.add(popup); ..... But when i roll the mouse over "popup", nothing is happening (i need to select an item from popu...
AES encryption - how to later decrypt the encrypted string ?
i have a java program . this is a AES encryption - decryption program. the program has a graphical user interface with can input string and show AES encrypted string. the program also shows original string by using decryption function written in the code. the interface is such that when string is entered and convert button is clicked the...
upload jar to respository
I have a jar files that cannot be found on maven2 repository. i interested to add the jar so i can just include extra tag in my pom.xml file and other developer can use the jar. what is the steps needed to upload the jar to http webserver webfolder? what file should i uploaded beside custom.jar ? what other files need to exist on the w...
JNI Java in c++
Hello I am trying to create Java Virtual Machine in a cplusplus program using the code as follows: JNIEnv *env; JavaVMInitArgs vm_args; JavaVMOption options[1]; options[0].optionString = "-Djava.class.path=D:\\Java Src\\TestStruct"; //Path to the java source code vm_args.version = JNI_VERSION_1_6; //JDK version. This indicates version ...
Encryption in Java & Flex
I want tp encrypt and decrypt string, with defined salt. But the result must be same if the code run in java and adobe flex. The main goal is: the app in adobe flex will be generate a string that can be decrypt in server using java. I use this flex library http://crypto.hurlant.com/demo/ Try to 'Secret Key' Tab. I want to use AES Encr...
Richfaces: dropDownMenu action
Hi! I understand, how to set action to rich:menuItem component, but can i somehow set action on rich:dropDownMenu? Parameter action cannot be set in rich:dropDownMenu component, only in dropDownMenus child rich:menuItem. Maybe there is another approach? Action setting to rich:menuItem: <rich:menuItem submitMode="server" value="#{msg.s...
Can/should I use WeakReference in my complex object structure with db4o?
I'm considering to port an application to db4o. The data model consists of lots of small objects with a lot of references between each other. For example, I have a book which points to an author and chapter. Chapters have sections, sections have large blobs of text, images, and they reference characters mentioned. I think it should be p...
Hibernate mapping collection by column
Hi there, lets take this example <class name="Product"> <id name="serialNumber" column="productSerialNumber"/> <property name="category" column="category" /> <set name="categories"> <key column="productSerialNumber_FK" not-null="true"/> <one-to-many class="Part"/> </set> The collection mapping always maps with the id from t...
What are java object fields initialized with?
Is it null for Object type? class C { int i; String s; public C() {} } will "s" be always null ? What about simple types as int? What will that be? Zero or an arbitrary value? What about local variables in methods? public void meth() { int i; } what is the unitialized value of i ? <Relying on such default values, however, i...
JavaFx on Linux 2.4.26/ARM9 Processor/200MHz/32MB RAM
Hi, I am new to JavaFx technology, I would like to know whether I can have JavaFx on a Linux kernel 2.4.26 (no other commercial distribution), it is a touch screen based navigation system runs on a ARM9 processor (200MHz, 32MB RAM). While searching, I found that JavaFx is supported on Linux platforms, but I couldn't find any reference ...
Encryption code segment which I do not understand
I am reading about encryption and having a lot of difficulty understanding these 3 Java statements of an encryption program. cipher = Cipher.getInstance("AES"); cipher.init(Cipher.ENCRYPT_MODE, skeySpec); encrypted = cipher.doFinal(str.getBytes()) Can somebody help? ...
How to import multiline csv files?
I got a file in this format. "abc";"def";"ghi asdasd asdasd asd asd aas d " Now i want to import it with Java. Does anyone know a library that support this kind of import? ...
[java] One step check for null value & emptiness of a string
I have a setter method. Then when another (say generate) method is run, I need to check the value of my fields. So in the case of String property, I need to know if it contains the value or if it was not set. So it may be null, "" or something meaningful, there are 3 possibilities. And it is rather boring to check first for a null value...