How to test if one java class extends another at runtime?
Are you looking for:
Super.class.isAssignableFrom(Sub.class)
If you want to know whether or not a Class extends another, use Class#isAssignableFrom(Class). For your example, it would be:
if(B.class.isAssignableFrom(A.class)) { ... }If you're interested in whether or not an instance is of a particular type, use instanceof:
A obj = new A();if(obj instanceof B) { ... }Note that these will return true if the class/instance is a member of the type hierarchy and are not restrictive to direct superclass/subclass relationships. For example:
// if A.class extends B.class, and B.class extends C.classC.class.isAssignableFrom(A.class); // evaluates to true// ...and...new A() instanceof C; // evaluates to trueIf you want to check for direct superclass/subclass relationships, Tim has provided an answer as well.
You want to know if b is assignable from a:
b.isAssignableFrom(a);Additionally, if you want to know that a is a direct subclass of b:
a.getSuperclass().equals(b);