Java Stream Collectors and Spliterators¶
In the Java utility framework, several classes are designed as companion or utility "helpers" (often pluralized) to their corresponding core interfaces or singular classes.^[600-developer-java-java-base-java-util.md] This pattern is evident in the Stream processing APIs, where functional interfaces are paired with utility classes for common operations.^[600-developer-java-java-base-java-util.md]
Stream Collectors¶
The java.util.stream.Collector interface is the primary abstraction for mutable reduction operations in the Stream API.^[600-developer-java-java-base-java-util.md] It is typically accompanied by java.util.stream.Collectors, which provides static factory methods for various useful reduction implementations, such as accumulating elements into Lists, Sets, or Maps.^[600-developer-java-java-base-java-util.md]
Spliterators¶
The java.util.Spliterator interface defines a mechanism for traversing and partitioning elements, a core component of the Java Stream API.^[600-developer-java-java-base-java-util.md] For creating or working with these iterators programmatically, the java.util.Spliterators utility class offers standard implementations and helper methods.^[600-developer-java-java-base-java-util.md]
Related Helper Classes¶
This pattern of pairing an interface with a utility helper class is consistent across the java.util package.^[600-developer-java-java-base-java-util.md] Other examples include:
- [[Java Collections]] (
java.util.Collectionvsjava.util.Collections) - [[Java Arrays]] (
java.lang.reflect.Arrayvsjava.util.Arrays) - [[Java Objects]] (
java.lang.Objectvsjava.util.Objects) - [[Java Files]] (
java.io.Filevsjava.nio.file.Files) - [[Java Paths]] (
java.nio.file.Pathvsjava.nio.file.Paths)
Sources¶
^[600-developer-java-java-base-java-util.md]