ninja-core/src/main/java/ninja/diagnostics/DiagnosticErrorBuilder.java
static public String getSourceCodeRelativePathForStackTraceElement(StackTraceElement ste) {
        String packageName = ste.getClassName();
        // e.g. com.fizzed.test.Application$1 for an internal class
        int pos = packageName.lastIndexOf('.');
        if (pos > 0) {
            packageName = packageName.substring(0, pos);
            return
                packageName.replace(".", File.separator)
                + File.separator
                + ste.getFileName();
        } else {
            // must be in default package
            return
                ste.getFileName();
        }
    }
static public String getSourceCodeRelativePathForStackTraceElement(StackTraceElement ste) {
        String packageName = ste.getClassName();
        // e.g. com.fizzed.test.Application$1 for an internal class
        int pos = packageName.lastIndexOf('.');
        if (pos > 0) {
            packageName = packageName.substring(0, pos);
            return
                packageName.replace(".", File.separator)
                + File.separator
                + ste.getFileName();
        } else {
            // must be in default package
            return
                ste.getFileName();
        }
    }
Calculates the relative path of the source code file of a StackTrace
element if its available. Uses the packageName of the class to create a relative path
and appends the "filename" included with the stack trace element.
@param ste The stack trace element
@return The relative path of the source code file or null if the information
wasn't available in the stack trace element.