Are optional non-capturing groups redundant? Is the following regex: semantically equivalent to the following regex? Answer Your (?:wo)?men and (wo)?men are semantically equivalent, but technically are different, namely, the first is using a non-capturing and the other a capturing group. Thus, the question is…
Is the String args[] parameter needed for programs that do not require command line arguments?
As far as I know, String args[] accepts an array of elements of type String – a mechanism through which the runtime system passes information to an application. If we take a simple addition program like this: It is obvious that the program does not need any command line arguments to calculate the result…
How to send and receive a DSA public/private signed message in Java
I cannot find any good (complete) documentation on how to exchange a public/private key signed message in Java. I have yet to find a concise document on the minimum steps needed to generate a public key and private key using DSA, sign a byte[], and verify it. The documentation from Oracle is too broken up and…
Convert a for loop to concat String into a lambda expression
I have the following for loop which iterates through a list of strings and stores the first character of each word in a StringBuilder. I would like to know how can I transform this to a lambda expression Answer Assuming you call toString() on the StringBuilder afterwards, I think you’re just looking for…
Declare an array in java without size
Hello am trying to declare an array in java but i do not want the array to have a specific size because each time the size must be different. I used this declaration: int[] myarray5; but when am trying the below code there is an error on myarray5 and also when am printing the array: Answer There is a NullPoin…
JSON Error “java.lang.IllegalStateException: Expected BEGIN_OBJECT but was STRING at line 1 column 1 path $”
This create Exception Big thanks for help. Answer Let’s look at the error you are receiving. Expected BEGIN_OBJECT Your JSON is an object, and all JSON objects are enclosed in curly braces ({}). BEGIN_OBJECT is therefore {. And it’s expecting it somewhere. but was STRING But instead he found a str…
How do I log a stacktrace using java’s Logger class
I am using Java’s Logger class. I want to pass ex.printStackTrace() into Logger.log(loglevel, String), but printStackTrace() returns void. So I am not able to pass and print the stack trace of the exception. Is there any way that I can convert void into String, or are there any other methods to print th…
After upgrading to Apache HttpClient 4.4 it does not send cookies with requests
I am using the Apache HttpClient to send requests to our internal API servers. The servers require authentication and need a cookie to be set with an auth token. Up to HttpClient 4.3.6 this has been working fine, but on 4.4 and above it has stopped sending the cookies on requests. My cookie domain is set to .…
Java – Check Not Null/Empty else assign default value
I am trying to simplify the following code. The basic steps that the code should carry out are as follows: Assign String a default value Run a method If the method returns a null/empty string leave the String as default If the method returns a valid string set the String to this result A Simple example would …
Edit the cell value at a dynamic TableView?
Is it possible to edit a cell value in a dynamic TableView (dynamic rows and dynamic columns)? All I found on the internet was some editable TextFields over the cells. However, I want to edit the value in the table and then update my List with the new data. I’m using IntelliJ IDEA 13.1.4 , JavaFX Scene …