ADDITIONAL SYSTEM INFORMATION :
openjdk version "11-ea" 2018-09-25
OpenJDK Runtime Environment 18.9 (build 11-ea+26)
OpenJDK 64-Bit Server VM 18.9 (build 11-ea+26, mixed mode)


A DESCRIPTION OF THE PROBLEM :
Base64.Encoder incorrectly handles arrays of sizes that approach Integer.MAX_VALUE. Due to a bug in the implementation, a NegativeArraySizeException may be thrown during encoding. Instead, it should either complete the encoding successfully, or throw an OutOfMemoryError.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
launch jshell:
jshell -R-Xmx8G

and execute the following 2 commands (the first will take quite some time):
byte[] input = new byte[Integer.MAX_VALUE-2];
byte[] output = Base64.getEncoder().encode(input);

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Either no exception occurs, or an OutOfMemoryError is thrown
ACTUAL -
| Exception java.lang.NegativeArraySizeException: -1431655768
| at Base64$Encoder.encode (Base64.java:265)
| at (#6:1)