JavaBean implementing Interface and overriding getter causing null pointer

thank you for fixing ROO-3584 - for the first time I cloned and built roo, tried it out - and it worked. but I discovered annother issue:

Interface:

public interface DemoInterface {
	
	public long getRank();
}

Bean:

@RooJavaBean
public class DemoEntity implements DemoInterface {

    private String name;

    private long rank;
    
    public long getRank() {
    	return this.rank;
    }    
}

causes:
NullPointerException at org.springframework.roo.addon.javabean.JavaBeanMetadata.checkIfInterfaceMethodWasImplemented(JavaBeanMetadata.java:607)