I was trying to convert list of Integers into String of comma separated integers. Collectors.joining(CharSequence delimiter) – Returns a Collector that concatenates the input elements, separated by …
Tag: java-8
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 …
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. org.springframework.beans.factory.BeanCreationException: Error creating bean …
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 Windows (e.g. not redirecting to /dev/null)
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 …
How do I use MapElements and KV in together in Apache Beam?
I wanted to do something like: PCollection
How to implement the Elvis operator in Java 8?
I have the classic “Elvis operator” case, where I’m calling methods that each may return null and chaining them together: In Java 8, the most faithful implementation I’ve found is something like this: I wish that Java’s Optional had something akin to the elvis operator: So that I wouldn’t have to wrap each return value: Is there a more efficient
What is the difference between intermediate and terminal operations?
can someone tell me What is the difference between intermediate and terminal operations for Stream? Stream operations are combined into pipelines to process streams. All operations are either intermediate or terminal ..means?. Answer A Stream supports several operations and these operations are divided into intermediate and terminal operations. The distinction between this operations is that an intermediate operation is lazy
Switching Keys in a Map of Maps
How would you use Java 8 streams to swap keys in this map of maps? Or at least clean up this mess a little bit… Map<Type1, Map> to Map<Type2, Map<Type1, String&…
Way to parseInt without try-catch in Java 8?
Is there a better way to try to convert to int a string that can be or not an integer? Integer.parseInt(String value) will work well with “25” or “019” but not with “hello&…