I’m making a GUI that display result of background calculations. But before that, I wanted to test changing the dataset. Here is my code: As you can see, I want to change points on the graph (every time it finishes ‘some complicated computations’) – this change is in the thread invoked…
Convert 4 bytes to an unsigned 32-bit integer and storing it in a long
I’m trying to read a binary file in Java. I need methods to read unsigned 8-bit values, unsigned 16-bit value and unsigned 32-bit values. What would be the best (fastest, nicest looking code) to do this? I’ve done this in c++ and did something like this: But in Java this causes a problem if for ex…
Resize an Array while keeping current elements in Java?
I have searched for a way to resize an array in Java, but I could not find ways of resizing the array while keeping the current elements. I found for example code like int[] newImage = new int[newWidth];, but this deletes the elements stored before. My code would basically do this: whenever a new element is a…
How to calculate properly actual month count between 2 dates?
I have followed method getDiffDateMap that calculates difference between 2 dates and returns Map of Integers that represent milliseconds, seconds, minutes, hours, days, months and years respectively. …
Epoch time confusion, clarification needed
Given: As i understand it, the result comes back with time since the epoch, in milliseconds The current time as UTC milliseconds from the epoch. Given that my test always sets the objects the same, why are results coming up different as time goes by? UPDATE: I continue to second guess myself due to For the sa…
Java enums – choice between fields, abstract methods, and class level map
I have written a Java enum where the values have various attributes. These attributes could be stored in any of the following ways: Using fields: Using abstract methods: Using class level map: How should I decide when to prefer which? Thanks! Answer (I am answering my own question so that I can share some thi…
How to search in a List of Java object
I have a List of object and the list is very big. The object is Now I have to search for a specific value of an object in the list. Say if value3==’three’ I have to return those objects (My search is not always based on value3) The list is What is the efficient way of doing it? Thanks. Answer
List to ArrayList conversion issue
I have a following method…which actually takes the list of sentences and splits each sentence into words. Here is it: public List getWords(List strSentences){ allWords = …
Java—how can I dynamically reference an object’s property?
In javascript, I can do this: Can I do anything close in Java? Answer Yes, you can do it by reflection with something along the following lines: However, if you are not very familiar with Java, this approach should be avoided if at all possible, as it is somewhat dangerous and error prone. For instance, there…
Create a List of byte[]
How might you go about creating a List of byte[] (not Byte)? I want something like the following: Answer That will work fine because arrays are objects in Java, so you can build Lists out of them. Note that only in Java 7 can you do In older versions you must restate the byte[]: This has been brought up alrea…