### Question:
WrapperType { public boolean isRoot() { return this == ROOT; } private  WrapperType(String name, WrapperType parent); static WrapperType of(String name); static WrapperType of(String name, WrapperType parent); @CheckForNull WrapperType getParent(); boolean isRoot(); boolean isAssignableFrom(@CheckForNull WrapperType type); @Override int hashCode(); @Override boolean equals(Object obj); @Override String toString(); static final WrapperType ROOT; static final WrapperType COMPONENT; static final WrapperType LAYOUT; static final WrapperType FIELD; }### Answer:
@Test public void testIsRoot() { assertTrue(WrapperType.ROOT.isRoot()); assertFalse(WrapperType.COMPONENT.isRoot()); assertFalse(WrapperType.FIELD.isRoot()); assertFalse(WrapperType.of("foo", null).isRoot()); assertFalse(WrapperType.of("", null).isRoot()); }