Check if a Class Object is subclass of another Class Object in Java

Question

I\'m playing around with Java\'s reflection API and trying to handle some fields. Now I\'m stuck with identifying the type of my fields. Strings are easy, just do myFi

Answer 1

You want this method:

boolean isList = List.class.isAssignableFrom(myClass);

where in general, List (above) should be replaced with superclass and myClass should be replaced with subclass

From the JavaDoc:

Determines if the class or interface represented by this Class object is either the same as, or is a superclass or superinterface of, the class or interface represented by the specified Class parameter. It returns true if so; otherwise it returns false. If this Class object represents a primitive type, this method returns true if the specified Class parameter is exactly this Class object; otherwise it returns false.

Reference:

• Class.isAssignableFrom(Class)

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Related:

a) Check if an Object is an instance of a Class or Interface (including subclasses) you know at compile time:

boolean isInstance = someObject instanceof SomeTypeOrInterface;

Example:

assertTrue(Arrays.asList("a", "b", "c") instanceof List);

b) Check if an Object is an instance of a Class or Interface (including subclasses) you only know at runtime:

Class typeOrInterface = // acquire class somehow
boolean isInstance = typeOrInterface.isInstance(someObject);

Example:

public boolean checkForType(Object candidate, Class type){
    return type.isInstance(candidate);
}