Context I want to iterate over a Spark Dataset and update a HashMap for each row. Here is the code I have: Issue My issue is that the foreach doesn’t iterate at all, the lambda is never executed and I don’t know why. I implemented it as indicated here: How to traverse/iterate a Dataset in Spark Java? At the end,
Tag: foreach
Is there a way to go back by one iteration in a for-each loop?
For example, if I were to do… If it isn’t possible, is there another method of traversing through some sort of collection class while controlling the iteration counter? I tried looking through the answers to this question but couldn’t think of a way that was clear to me. Any suggestions are appreciated! Answer It depends on what you are trying
Can I run a while loop inside a for loop? [Java] If so, how would I do it in this scenario?
Im doing some simple maths using loops and my task is as follows: “Given an integer,N , print its first 10 multiples. Each multiple N * i (where 1 <= N <= ) should be printed on a new line in the form: N x i = result.” My input has to be : My output: Sample Input: Sample Output:
Using Java stream forEach() in ScheduledExecutorService freezes
The general idea is to have a Runnable running every 10 seconds in background to check some data and if needed make changes in an object. ScheduledExecutorService is instantiated in method main() and the task is scheduled. Runnable task instantiates Crawler object and starts crawling. Most of the times it runs couple of times with success but when application is
Does Kotlin’s version of Java’s for each have the same limitations?
I’m currently learning Kotlin coming from Java. In Java, doing for(String s:stringList){ if(condition == true) stringList.remove(s); } doesn’t work, as you can only read data with for each. Does …
Serialization process constantly overwrites itself?
I’m fairly new to java and trying to do some serialization in my project. I have a bunch of objects called Student and I would like to serialize them. The code I’m using for this is as follows: The issue I’m finding is that the students array I’m using has twenty students (S1 – S20). When I attempt to deserialize
Difference between Arraylist.forEach() and Arraylist.replaceAll()
I have a question about the difference between Arraylist.forEach() and Arraylist.replaceAll(). I know that Arraylist.forEach() is used to perform an action for each element in the list, but it seems that Arraylist.replaceAll() does the exact same thing. But for some reason, when you decide to do a.forEach(e -> e.concat(“test”); assuming a is an Arraylist of Strings, the Arraylist does not
Using Lambda and Streams in For each and returning result
i am have been learning lambda and streams lately and have kind of been thrown into the deep end really early. I currently have an array list of books, a user types in a word and if the word equals the books author or title, the books toString(all attributes of the book nicely formatted) is called and returned. Very easy
How can I make my class iterable so I can use foreach syntax?
I have Book and BookList classes. BookList is something like this: In my main class I want to print titles of books with in a for each loop: Eclipse says: Can only iterate over an array or an instance of java.lang.Iterable How can I get this working? Answer You need to implement the Iterable interface, which means you need to
How to avoid java.util.ConcurrentModificationException when iterating through and removing elements from an ArrayList
I have an ArrayList that I want to iterate over. While iterating over it I have to remove elements at the same time. Obviously this throws a java.util.ConcurrentModificationException. What is the best practice to handle this problem? Should I clone the list first? I remove the elements not in the loop itself but another part of the code. My code