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);
});
}
}