Java ProcessBuilder.redirectErrorStream() is a method in the Java ProcessBuilder class that merges the standard error stream with the standard output stream of an external process. This allows for handling both types of output together, simplifying output processing. Introduced in Java 2004 with Java 5, redirectErrorStream() is often used in system administration and automation tasks where output needs to be captured in a single stream.

https://docs.oracle.com/javase/8/docs/api/java/lang/ProcessBuilder.html