To write to standard error in Java, you can use the System.err.println() method. This method works similarly to System.out.println(), but instead of writing to the standard output, it writes to the standard error stream.

public class ErrorOutputExample {
    public static void main(String[] args) {
        System.err.println("This is an error message.");
    }
}

In the example above, we have a simple Java program that writes the error message “This is an error message.” to the standard error stream.

By default, the standard output (System.out) and the standard error (System.err) streams are both displayed on the console. However, they can be redirected to different locations if desired.

To capture the standard error output and write it to a file, you can use shell redirection when running your Java program. For example, to redirect the standard error stream to a file named “error.log”, you can use the following command:

java ErrorOutputExample > error.log 2>&1

The 2>&1 part of the command redirects the standard error stream to the same file as the standard output.

In addition to using System.err.println(), you can also use System.err.print() to write error messages without appending a newline character.

Writing to standard error is particularly useful when you want to separate error messages from regular output or when you want to capture and analyze error logs.

So, the next time you encounter an error or need to log important information during Java application development, make use of the System.err stream to conveniently write to the standard error output.

#Java #StandardError #ErrorOutput