src/main/java/org/jfree/graphics2d/svg/StandardFontMapper.java
public String get(String family) {
        Args.nullNotPermitted(family, "family");
        return this.alternates.get(family);
    }
public String get(String family) {
        Args.nullNotPermitted(family, "family");
        return this.alternates.get(family);
    }
Returns the mapped (alternate) font family name.

@param family  the font family ({@code null} not permitted).

@return The alternate font family name (possibly {@code null}).