src/main/java/org/jfree/graphics2d/svg/SVGGraphics2D.java
public String getSVGDocument() {
        StringBuilder b = new StringBuilder();
        b.append("<?xml version=\"1.0\"?>\n");
        b.append("<!DOCTYPE svg PUBLIC \"-//W3C//DTD SVG 1.0//EN\" ");
        b.append("\"http://www.w3.org/TR/2001/REC-SVG-20010904/DTD/svg10.dtd\">\n");
        b.append(getSVGElement());
        return b.append("\n").toString();
    }
public String getSVGDocument() {
        StringBuilder b = new StringBuilder();
        b.append("<?xml version=\"1.0\"?>\n");
        b.append("<!DOCTYPE svg PUBLIC \"-//W3C//DTD SVG 1.0//EN\" ");
        b.append("\"http://www.w3.org/TR/2001/REC-SVG-20010904/DTD/svg10.dtd\">\n");
        b.append(getSVGElement());
        return b.append("\n").toString();
    }
Returns an SVG document (this contains the content returned by the
{@link #getSVGElement()} method, prepended with the required document
header).

@return An SVG document.