innerGroup.defineTemplate("samegroup", "x", "hi ");
ST st = innerGroup.getInstanceOf("test");
st.add("m", 10);
STGroup outerGroup = new STGroup();
outerGroup.defineTemplate("errorMessage", "x", "<x>");
ST outerST = outerGroup.getInstanceOf("errorMessage");
outerST.add("x", st);
String expected = "hi ";
String result = outerST.render();