StackOverflow Exception when calling super.method when extending java class

package test.java;

public abstract class A<T> {
    protected String getText(T arg){
        return "Class A.";
    }
}

package test.java;

public class C extends A<String> {
    @Override
    protected String getText(String arg){
        return super.getText(arg) + "Class C. ";
    }
}

package test.java

class D extends C {
    @Override
    protected String getText(String arg) {
        return super.getText(arg) + 'Class D.';
    }

    public static void main(String[] args) {
        D d = new D();
        String res = d.getText(null);
        println(res);
    }
}

Exception in thread "main" java.lang.StackOverflowError
	at test.java.D.getText(D.groovy)
	at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:601)
	at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:90)
	at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:233)
	at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1085)
	at org.codehaus.groovy.runtime.ScriptBytecodeAdapter.invokeMethodOnSuperN(ScriptBytecodeAdapter.java:128)
	at test.java.D.getText(D.groovy:6)
	at test.java.D.getText(D.groovy)