ExceptionUtils.java

public class ExceptionUtils {
    public static String stackTraceAsString(Exception ex) {
        if (ex == null) {
            return "";
        }

        return Arrays.asList(ex.getStackTrace())
                .stream()
                .reduce(
                        new StringBuilder(),
                        (builder, frame) -> {
                            builder.append(frame.toString());
                            return builder;
                        },
                        (b1, b2) -> {
                            return new StringBuilder(b1.toString() + "\n" + b2.toString());
                        })
                .toString();
    }
}