Random shuffling of an array
Using Collections to shuffle an array of primitive types is a bit of an overkill… It is simple enough to implement the function yourself, using for example the Fisher–Yates shuffle:
Java
Choosing the best concurrency list in Java
had better be List The only List implementation in java.util.concurrent is CopyOnWriteArrayList. There’s also the option of a synchronized list as Travis Webb mentions. That said, are you sure you need it to be a List? There are a lot more options for concurrent Queues and Maps (and you can make Sets from Maps), and those structures tend to make the most sense for many of the … Read more
UnsatisfiedDependencyException: Error creating bean with name
The ClientRepository should be annotated with @Repository tag. With your current configuration Spring will not scan the class and have knowledge about it. At the moment of booting and wiring will not find the ClientRepository class. EDIT If adding the @Repository tag doesn’t help, then I think that the problem might be now with the ClientService and ClientServiceImpl. Try to annotate the ClientService (interface) with @Service. … Read more
UnsatisfiedDependencyException: Error creating bean with name
The ClientRepository should be annotated with @Repository tag. With your current configuration Spring will not scan the class and have knowledge about it. At the moment of booting and wiring will not find the ClientRepository class. EDIT If adding the @Repository tag doesn’t help, then I think that the problem might be now with the ClientService and ClientServiceImpl. Try to annotate the ClientService (interface) with @Service. … Read more
Add an object to an Array of a custom class
If you want to use an array, you have to keep a counter which contains the number of cars in the garage. Better use an ArrayList instead of array:
Extracting .jar file with command line
From the docs: To extract the files from a jar file, use x, as in: To extract only certain files from a jar file, supply their filenames: The folder where jar is probably isn’t C:\Java for you, on my Windows partition it’s: Unless the location of jar is in your path environment variable, you’ll have to specify the full path/run the program from … Read more
Error: cannot find symbol ArrayList
Do you have an import statement in the top of the file?
JRE 1.7 – java version – returns: java/lang/NoClassDefFoundError: java/lang/Object
When running any java application, or just ‘java’, the jvm fails: Error occurred during initialization of VMjava/lang/NoClassDefFoundError: java/lang/Object Here is a list of wrong answers: The correct Java home directory, including the /bin directory, is on the global PATH JAVA_HOME is set correctly Executing the command java -fullversion works$ java -fullversion ./java full version “1.7.0_05-b05” The symbolic … Read more
Error: JavaFX runtime components are missing, and are required to run this application with JDK 11
This worked for me: File >> Project Structure >> Modules >> Dependency >> + (on left-side of window) clicking the “+” sign will let you designate the directory where you have unpacked JavaFX’s “lib” folder. Scope is Compile (which is the default.) You can then edit this to call it JavaFX by double-clicking on the … Read more
How to get rid of Checkstyle message ‘File does not end with a newline.’
Put a newline at the end of the fileorconfigure CheckStyle not to care. You also have to tell the Maven Checkstyle plugin to use your checkstyle config file.