How do you return an ArrayList from a function in Java?

Can a function return an ArrayList in Java?

Return an ArrayList From a Non-Static Function in Java

We will work with a function that creates and returns an ArrayList of some size. … This function is non-static, so an object of the class will be needed to invoke it. In the following code, we create such a function.

How do you return an ArrayList from a function?

add(3); return(numbers); } } public class T{ public static void main(String[] args){ Test t = new Test(); ArrayList<Integer> arr = t. myNumbers(); // You can catch the returned integer arraylist into an arraylist. } }

How do you return a list from a method in Java?

The list() method of java. util. Collections class is used to return an array list containing the elements returned by the specified enumeration in the order they are returned by the enumeration. This method provides interoperability between legacy APIs that return enumerations and new APIs that require collections.

How do you return an ArrayList to a String in Java?

Approach:

1. Get the ArrayList of String.
2. Convert ArrayList to Object array using toArray() method.
3. Iterate and convert each element to the desired type using typecasting. Here it is converted to String type and added to the string array.
4. Print the string array.

How do you return an ArrayList to an ArrayList in Java?

4 Answers. If you cannot change the signature and it is mandatory to return an arraylist, then you can create an arraylist with just one element and return it. Something like this: ArrayList returnList = new ArrayList(); returnList.

What is the return type of ArrayList in Java?

So the method get , which is the method we described above, is documented as having argument type int and return type E meaning that if get is called on an object of type ArrayList<Integer> it returns an Integer , if it is called on an object of type ArrayList<String> it returns a String , and so on.

How do you return an empty ArrayList in Java?

Method 1: Using clear() method as the clear() method of ArrayList in Java is used to remove all the elements from an ArrayList. The ArrayList will be completely empty after this call returns. Return Value: This method does not return any value.

How do I print an ArrayList in reverse order?

To reverse an ArrayList in java, one can use Collections class reverse method i.e Collections. reverse() method. Collections reverse method reverses the element of ArrayList in linear time i.e time complexity is O(n). Collections reverse method accepts a List type as an argument.

How do I return an ArrayList in C#?

You can just put return null; or return new ArrayList(); since it looks like you don’t care with what you’re gonna get with the catch.

How do you return a list from a method?

4 Answers. There is no need to initialize the variable to an empty list that will get replaced immediately. If the list is very large or you simply need to traverse it, you can use the yield keyword and change the return type of the function to IEnumerable<string> , though your current design doesn’t fit this pattern.

How do I return an ArrayList long?

You can fix this by explicitly telling Java to interpret the numbers as long , you do so by appending l or L after the number: new ArrayList<Long>(Arrays.

How do I return two lists in Java?

You can just return them in an array. There is no easy way to do this in Java. You can create a small wrapper class to contain both elements, you can return a list of both lists, a set of both lists, or a Map> containing 2 entries with both lists. Add your lists ( eventList and emailList ) to this super list.