InputStream.transferTo() method should specify what the return value should be when the number of bytes transfered is larger than Long.MAX_VALUE

Summary

Specify that the transferTo methods of InputStream and Reader in the java.io package and java.util.zip.ZipInputStream::transferTo return at most Long.MAX_VALUE.

Problem

InputStream::transferTo and Reader::transferTo may transfer more than Long.MAX_VALUE bytes or characters, respectively, but in both cases, the counter of the number of values transferred will overflow a long.

Solution

Clamp the value returned by transferTo to Long.MAX_VALUE and specify that if more than that number of values is transferred, then Long.MAX_VALUE will be returned.

Specification

--- a/src/java.base/share/classes/java/io/InputStream.java
+++ b/src/java.base/share/classes/java/io/InputStream.java
@@ -769,6 +769,9 @@ public boolean markSupported() {
      * interrupted during the transfer, is highly input and output stream
      * specific, and therefore not specified.
      * <p>
+     * If the total number of bytes transferred is greater than {@linkplain
+     * Long#MAX_VALUE}, then {@code Long.MAX_VALUE} will be returned.
+     * <p>
      * If an I/O error occurs reading from the input stream or writing to the
      * output stream, then it may do so after some bytes have been read or
      * written. Consequently the input stream may not be at end of stream and

--- a/src/java.base/share/classes/java/io/Reader.java
+++ b/src/java.base/share/classes/java/io/Reader.java
@@ -421,6 +421,9 @@ public void reset() throws IOException {
      * interrupted during the transfer, is highly reader and writer
      * specific, and therefore not specified.
      * <p>
+     * If the total number of characters transferred is greater than {@linkplain
+     * Long#MAX_VALUE}, then {@code Long.MAX_VALUE} will be returned.
+     * <p>
      * If an I/O error occurs reading from the reader or writing to the
      * writer, then it may do so after some characters have been read or
      * written. Consequently the reader may not be at end of the stream and