How to get ArrayList from Stream in Java 8

Given a Stream, the task is to convert this Stream into ArrayList in Java 8.

Examples:

Input: Stream: [1, 2, 3, 4, 5]
Output: ArrayList: [1, 2, 3, 4, 5]

Input: Stream: ['G', 'e', 'e', 'k', 's']
Output: ArrayList: ['G', 'e', 'e', 'k', 's']

1. Using Collectors.toList() method:
   1. Get the Stream to be converted.
   2. Collect the stream as List using collect() and Collectors.toList() methods.
   3. Convert this List into an ArrayList
   4. Return/Print the ArrayList

   Below is the implementation of the above approach:

   Program:

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   // Java program to convert Stream to ArrayList // using Collectors.toList() method    import java.util.*; import java.util.stream.*;    public class GFG {        // Function to get ArrayList from Stream     public static <T> ArrayList<T>     getArrayListFromStream(Stream<T> stream)     {            // Convert the Stream to List         List<T>             list = stream.collect(Collectors.toList());            // Create an ArrayList of the List         ArrayList<T>             arrayList = new ArrayList<T>(list);            // Return the ArrayList         return arrayList;     }        // Driver code     public static void main(String args[])     {            Stream<Integer>             stream = Stream.of(1, 2, 3, 4, 5);            // Convert Stream to ArrayList in Java         ArrayList<Integer>             arrayList = getArrayListFromStream(stream);            // Print the arraylist         System.out.println("ArrayList: " + arrayList);     } }

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   Output:

   ArrayList: [1, 2, 3, 4, 5]
   

2. Using Collectors.toCollection() method:
   Approach:
   1. Get the Stream to be converted.
   2. Collect the stream as ArrayList using collect() and Collectors.toCollection() methods.
   3. Return/Print the ArrayList

   Below is the implementation of the above approach:

   Program:

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   // Java program to convert Stream to ArrayList // using Collectors.toList() method    import java.util.*; import java.util.stream.*;    public class GFG {        // Function to get ArrayList from Stream     public static <T> ArrayList<T>     getArrayListFromStream(Stream<T> stream)     {            // Convert the Stream to ArrayList         ArrayList<T>             arrayList = stream                             .collect(Collectors                             .toCollection(ArrayList::new));            // Return the ArrayList         return arrayList;     }        // Driver code     public static void main(String args[])     {            Stream<Integer>             stream = Stream.of(1, 2, 3, 4, 5);            // Convert Stream to ArrayList in Java         ArrayList<Integer>             arrayList = getArrayListFromStream(stream);            // Print the arraylist         System.out.println("ArrayList: "                            + arrayList);     } }

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   Output:

   ArrayList: [1, 2, 3, 4, 5]
   

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