java 8 - Do terminal operations close the stream?

Question

dirPath contains 200k files. I want to read them one by one and do some processing. The following snippet causes java.nio.file.FileSystemException: dirPath/file-N Too many open files. Isn't the terminal operation forEach() supposed to close the open stream (i.e. the open file) before moving to the next one? In other words, do I have to add try-with-resources for the streamed files?

Files.list(dirPath)
     .forEach(filePath -> {
              Files.lines(filePath).forEach() { ... }
              });

Answer 1

No forEach does not close the stream (created by Files.list or Files.lines). It is documented in the javadoc, for example for Files.list:

The returned stream encapsulates a Reader. If timely disposal of file system resources is required, the try-with-resources construct should be used to ensure that the stream's close method is invoked after the stream operations are completed.