I have a List of String arrays that I need to write into a CSV file efficiently. I’ve tried it two ways below. Dataset is a file with at least 1 million records in size. ie. returnedList has at least 1 million String[] arrays. My current code is terribly inefficient and takes far too long using the StringBuilder: My second
Jackson JsonRootName doesn’t add any root value
I am serialising an object, which I’d like to put a root value for. This is my class. This is how I am serialising it: But the serialised value is: While I was hopping to have a root json value as fed in the class definition. Could you help with that please? Answer Output: You need to enable WRAP_ROOT_VALUE on
SharedPreferences vs SQLite Database vs Room Database, which should I use for my project and why? Pros and Cons [closed]
I have a custom ListView of Semesters, a Semester is an object, in the MainActivity of an app I’m developing to learn more about Android developing and databases. That ListView is created by the user …
How can you draw rectangles on a JPanel?
I’m trying to create a program that generates rectangles using a slider. The user should be able to move the slider and rectangles should appear on the JPanel above the slider with random positions. I have tried running the program but I’m still unable to display anything, I move the slider but nothing appears on screen. I have tried coding
Backward Traverse using ListIteartor in java
I am new to java and learning from a very basic level. I am trying to run this below code which is not showing any result in the console. It’s only working when I add forward traverse code before it. Can anyone please help me with that? Thanks Answer When you create a list iterator with a call to myList.listIterator(),
Is there an example where the Java code repeatedly executes its own code? [closed]
Closed. This question needs details or clarity. It is not currently accepting answers. Want to improve this question? Add details and clarify the problem by editing this post. Closed 2 years ago. Improve this question Example: How can the value of the variable a be printed again after a restart of the application? Answer When you restart the application the
How can I resize a rectangular image to a square image while maintaining aspect ratio in Java?
I need to resize rectangular images (400×600) into square images (600×600) while keeping aspect ratio of the original image. The newly added pixels need to be transparent. Like this. I need it in java or kotlin code. But if that’s not possible then I don’t mind a solution in any other language. I have not been able to find a
How to increment numbers using Event Listeners and Widget Viewer in Java?
I’m writing a WidgetViewer GUI where when the “go up/up” button is pushed, a random number between 1 and 10 (inclusive) is generated and added to the left label, and another random number …
Possible to remove Title bar from JFileChooser?
I am trying to display a simple JFileChooser that has no Titlebar. Below is the example code: So essentially I want the Border I set to be the top level Title bar. Example image: So far I have had zero luck achieving this, nor found any others looking for a similar appearance. Appreciate the help! Cheers Answer The JFileChooser is
Function “onButtonClicked” is never use
I have created a function called “onButtonClicked” and I want the button (bt301_tw) to send me to the activity (MainActivity_04_ReadioGroup). The problem is when I create the function …