I was trying to convert a list of Integers into a string of comma-separated integers. Collectors.joining(CharSequence delimiter) – Returns a Collector that concatenates the input elements, separated by the specified delimiter, in encounter order. I am getting an error in line number 8: The method collec…
Tag: java-8
How to write this method in a generic way in java
Currently, I have this method implemented for five different class to configure FlatFileReader for five different text files and load into DB table. I would like to know is there a way to implement this method in a common place So that my each file will call this method to configure my reader to read their co…
Java stream/collect: map one item with multiple fields to multiple keys
I have the following code that I’d like to try to write using the java collectors. Given 2 attributes (firstname and lastname) of a person, I’d like to get a map containing the unique firstname or lastname as a key, and the list of the corresponding persons. Here’s a set of data : Output (as…
Linkedin parseq. How to run task after task?
I’m using parseq framework for asynchronous computation. Consider the following code. It first queries the content of google.com and then map the content to it’s length. Finally, the length is printed. The problem is that only the first task is ran. Why? Answer I was able to solve your problem wit…
Java compiler: How can two methods with the same name and different signatures match a method call?
I have this class called Container: and the class called Token: and finally a test class for the Token class The test compiles and runs just fine in eclipse. When building on the commad line a compile error is raised: The compilation also fails when I change line 21 to one of When I change the line to one of
Java(8): How to extract an specific class item from objects array?
I need to work on an Objects array which has the following value: The code which creates the objects array is: I need to extract a value from the ApplicationConfiguration type item. Note that it is not always the first array item! For start, I tried to do the following: in order to get a list with the specifi…
IllegalStateException: “Duplicate key” for Collectors.toMap()
Reference Question: Numbers which constitute the Maximum sum I was writing a program which would print the elements which have constituted to the maximum sum. I have been able to pass through any random scenario but when my maximum sum constitutes of two sets, my code fails. My code: For example when i am giv…
flyway schema giving IllegalArgumentException
On running flyway schema I’m receiving this exception.using Java 8 with spring boot. Flyway is not able to initialize. Answer Check the flyway_schema_history table, there you will see that you have an entry with installed_rank value set to 0, delete the row and run your application again. This will sort…
Java ProcessBuilder: How to suppress output instead of redirecting it
I’m using a ProcessBuilder to execute commands and redirect the output. I now want to add the possibility to have no output at all. Of course I could redirect into a file, but this would leave unnecessary files on the users system. I am looking for a solution that works on all platforms, including Windo…
How to convert mm/dd/yy string to “Monday 7th Jan”
I have a database file with mm/dd/yy values for events, and I want to display the date as something similar to “Day(word), day(number), month(word)”. 01/07/19 into Monday 4th Jan or Monday 4 Jan or something similar. Answer You can use SimpleDateFormat to convert the string to date and then conver…