Java
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Java OO design help – how to abstract a save method?
I have a preference class (module) for several different applications Basically, it is the cache of preferences, so th…… -
java – ArrayList . Contain gives strange output
Who can explain? I have an ArrayList with a string I'm using it! arraylist. Contain to make sure I don't add duplicate…… -
Java – Scala: ‘Val’ is not initialized
In Java, I can easily do the following: final String str; if (p() == true) { str = "foo"; } else { str = "bar"…… -
How to use pdfbox to digitally sign dynamically created PDF documents?
I'm sorry! I'm poor in Java Please correct me where I am wrong and improve where I am poor! I'm trying to use PDF@R_77…… -
Java – how to check that we use Oracle 8i database in JDBC?
In JDBC, how to check that we are using Oracle 8i database? Solution Connection connection = DriverManager.getConnecti…… -
Java – if I call a static method, does the constructor run
I have a class named tile with a static method public static buffered image grass(). The class also has a constructor …… -
Java – error: unable to find or load the main class < < why do I receive this error?
I don't seem to be able to make this code work properly This is the mistake I keep getting: What caused this? Payroll3…… -
You can overload the finalize () method in Java
I've read a method, and each method can be overloaded It's a method, of course But when searching, I also found that y…… -
Java – vector and arraydeque classes
What is the difference between the vector and arraydeque classes? I read about the arraydeque class yesterday, and I u…… -
Java – why consider numeric values using the int parameter method?
class Test { class Test { void m1(byte b) { System.out.print("byte"); } void m1(short s) { System.out.…… -
Java Swing application message dialog help
I'm working on Java Swing applications I need to create a dialog box as shown in the figure I don't know the name; I c…… -
Java vector warning
I'm not sure what's wrong with my code public Vector blob (Pixel px) { Vector v = new Vector(); Point p = new…… -
Java: basic math errors?
I have to do something fundamentally wrong here My code is very simple: private static final long MILLIS_PER_YEAR = 10…… -
Java – why are there unhandled exceptions in this code?
I am from the following code: class Animal{ public void eat() throws Exception {} } class Dog extends Animal{ …… -
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Java – null pointer exception on actionbar on fragmentactivity
I received this error while running Stack trace: 01-22 06:32:55.509: E/AndroidRuntime(3728): FATAL EXCEPTION: main 01-…… -
Casting – Java 8 – filtering collections with external parameters
I have an animal map containing specific successors MyBaSEObjectAnimalMap.values().stream(). filter(x -> x ins…… -
Get a random subset from the result set in Java
I have a set of 100 objects I'm doing this now, but it only returns one object int size = memberSet.size(); Set&…… -
Java – this method must override the superclass method
I recently updated my computer to Ubuntu 11.10 64 bit I had a problem importing the project and it gave me an error "O…… -
Java null corresponds to double
I don't know how to raise the question or what title to use I hope I don't break any rules Anyway, can someone explain…… -
Doctrine ORM – doctrine 2 case sensitive queries
For some reason, I need to query "case sensitive" 2 in MySQL principles Is it possible? either $em->find('UserEn','…… -
My java if statement doesn’t seem to work
I don't know why, but when I use zxing to get barcodes in my Android application, the format is returned as EAN_ 13 bu…… -
Java – decimal conversion error
I'm writing a program to convert octal numbers to decimals It compiles correctly and everything, but my conversion cod…… -
Java – which method in jsoup can return modified HTML?
When I use jsoup to parse HTML files (stored locally) I modified some elements in the HTML file, so I want to save the…… -
Java – uses an object as a variable in the constructor
I have a question about using objects as variables in constructors It may be simple, but I really can't think of what …… -
Java – returns a static HTML without redirection in spring
So I want to return to the HTML page without sending a redirect The reason is that the URL in the browser is changed b…… -
Java – @ postconstruct is called multiple times for the @ conversationscoped bean
I have a @ conversationscoped bean with a start method, as follows: @postconstruct public void start() { if (conve…… -
How to update tableview items outside JavaFX thread
I have a table view of list user friends. I need to update it every 5 seconds with the data I retrieve from the databa…… -
Java – why not call the constructor of the class that implements the runnable interface?
I try to use the constructor of the class that implements the runnable interface But I was surprised to find that it h…… -
Each time the new operator is called, Java creates a new object
In Java, when we call a new constructor (), a new object will be created each time, that is; Allocate new memory or as…… -
Java – warnings when using reflection and generics
How can I rewrite: <T> T callMethod(String methodName,Object[] parameters) throws ... { ... return (T) S…… -
Java security class cast exception
Hi, I'm a beginner of Java security. I encountered the following problems when calling: Cipher cipher = Cipher.getInst……