Difference between intermediate and terminal operations in Java 8

Java Server Side Programming Programming

Stream is introduced in Java 8, it is only used for processing group of data not for the storting elements.. It does not modify the actual collection, they only provide the result as per the pipelined methods.

Stream api supports multiple operations and operations are divided into two parts −

Intermediate Operation- These operations are used to pipeline other methods and to transform into the other streams. They don’t produce results because these operation does not invoke until the terminal operation gets executed. Below are the examples −
sorted(Comparator<T>)
peek(Consumer<T>)
distinct()
Terminal operations - These operations are used to produce results. They can’t be used for chaining the other methods. Below are the examples −
forEach
count
toArray

Sr. No.	Key	Intermediate Operations	Terminal Operations
1	Basic	These operations are used to pipeline other methods and to transform into the other streams	A terminal operation in Java is a method applied to a stream as the final step.
2	Return Type	They only return another stream.	They return final result.
3	Method	sorted(Comparator<T>) peek(Consumer<T>) distinct()	forEach count toArray
4.	Use Case	These operations should be used to transform stream into another stream	They can be used to produce results.

Example of Intermediate and Terminal Operation

public class Main {
   public static void main(String args[]) throws InterruptedException, ExecutionException {
      List<String> laptopList = new ArrayList();
      laptopList.add("DELL");
      laptopList.add("ACER");
      laptopList.add("HCL");

      // Intermediate operation
      laptopList.sort((p1, p2) -> p1.compareTo(p2));

      // Terminal Operation
      laptopList.forEach(a -> {
         System.out.println(a);
      });
   }
}

Himanshu shriv

Updated on: 09-Sep-2020

12K+ Views

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