I am trying to implement the top-down merge sort algorithm in Java, using the pseudocode from Wikipedia. My problem is that my code sometimes throws a StackOverflowError, but not always. I have checked that my code matches the pseudocode several times and cannot find what is wrong with it. Here is my Java cod…
Debugging COM interface mapping in JNA
After mapping Vss.h and several others headers to Java/JNA (see this question) I am trying to run some of the COM object methods and have a problem debugging them. I do not know if I am calling the correct method or one with similar parameters. Some of the error codes I find in the JNA documentation here, but…
Why is @Validated required for validating Spring controller request parameters?
With the following validation setup in an annotated MVC controller: @Validated on the controller is required for the method parameter since it’s not a “complex” object. In comparison, the @Valid annotation on the setOther method works without the @Validated annotation. Why is @Validated requ…
How can I remove this java exception error in my code?
When I input a string into the code below by mistake as a test, I get a red java error message in my console. However, within my if statement I added an else part which should end the program if the user doesn’t input the if statement condition i.e a number between 0-100. Why this is and how can I
My JPanel doesn’t show after adding the paint method
I recently created my first board for my first board game and draw the board multiple ways on my JPanel.I finally decided to use Label, but since I needed to add pictures to that label, I had to change it into JLabel.The syntax is correct, but the Jlabels do not show. I tried cleaning my paint method and It s…
How to avoid java.lang.NullPointerException in my Code?
I have asked a question about my code for a Game of Life Implementation. The suggested solution solved my problem but created a new one. Now if I try to call the getCell() method I get a java.lang.NullPointerException. How can I avoid this exception? Link to my previous question with the corresponding code an…
How to properly filter Spring REST data
I have a Spring Data REST service with a single @Entity and Repository. When I run $ curl localhost:8080/api I get all the data stored in my repository and it works as expected. I also have a small React front end and I display that data there. My question is: Where should I filter the data? For example maybe…
Inputting a string into my code that an int is required and I get a java error how can I fix this?
When I input a string into the code below by mistake as a test, I get a red java error message in my console. However, within my if statement I added an else part which should end the program if the user doesn’t input the if statement condition i.e a number between 0-100. Why this is and how can I
JavaFX: How to overwrite button action in custom Dialog
I work on desktop application based on JDK 8 and JavaFX. I created custom dialog class with 2 buttons(finish and cancel). My goal is to return the list of strings added in dialog (after clicking finish button, dialog returns list. Cancel makes return empty list). I have problem, beacause function showAndWait …
Can we use semicolon independently at the beginning of a for-loop?
What is the meaning of this type of syntax in the for-loop? Answer A for statement is composed of 3 parts for(statement A; statement B; statement C): Statement A is the initializer statement. It is executed only one time. Usually, you create your variables you want to use in the for loop Statement B is the st…