Stream.Builder build() in Java

Last Updated : 6 Dec, 2018
Stream.Builder build() builds the stream, transitioning this builder to the built state. Syntax : 
Stream<T> build()
Exceptions :
  • IllegalStateException : If the builder has already transitioned to the built state, IllegalStateException is thrown. It signals that a method has been invoked at an illegal or inappropriate time. In other words, the Java environment or Java application is not in an appropriate state for the requested operation.
Return Value : The built stream. Note : A stream builder has a lifecycle, which starts in a building phase, during which elements can be added, and then transitions to a built phase, after which elements may not be added. The built phase begins when the build() method is called, which creates an ordered stream whose elements are the elements that were added to the stream builder, in the order they were added. Example 1 : Java 
// Java code to show the implementation
// of Stream.Builder build()
import java.util.stream.Stream;

class GFG {

    // Driver code
    public static void main(String[] args)
    {

        Stream.Builder<String> str_b = Stream.builder();

        str_b.add("Geeks");
        str_b.add("for");
        str_b.add("GeeksforGeeks");
        str_b.add("Data Structures");
        str_b.add("Geeks Classes");

        // creating the string stream
        Stream<String> s = str_b.build();

        // printing the elements
        s.forEach(System.out::println);
    }
}
Output : 
Geeks
for
GeeksforGeeks
Data Structures
Geeks Classes
Example 1 : Java 
// Java code to show the implementation
// of Stream.Builder build()
import java.util.stream.Stream;

class GFG {

    // Driver code
    public static void main(String[] args)
    {

        Stream.Builder<String> str_b = Stream.builder();

        str_b.add("Geeks");
        str_b.add("for");
        str_b.add("GeeksforGeeks");
        str_b.add("Data Structures");
        str_b.add("Geeks Classes");

        // creating the string stream
        Stream<String> s = str_b.build();

        // printing the elements
        s.forEach(System.out::println);
    }
}
Output : 
Geeks
for
GeeksforGeeks
Data Structures
Geeks Classes
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