Passing Class type as a parameter

Question

I have two methods like this

public void updateA (Object obj) throws CommonException
{
  if ( !(obj instanceof A) )
  {
     throw new CommonException(obj);
  }
  // other codes  
}


public void updateB (Object obj) throws CommonException
{
  if ( !(obj instanceof B) )
  {
     throw new CommonException(obj);
  }
  // other codes  
}

Now I want to extract the instance checking part into a separate method. Is it possible to do as follows?

public void chkInstance (Object obj, Class classType) throws CommonException
{
  if ( !(obj instanceof classType) )
  {
     throw new CommonException(obj);
  }
}

Answer 1

Use Class.isInstance :

if(!(classType.isInstance(obj)) {
    // ...
}

The documentation actually flat-out states (emphasis mine):

Determines if the specified Object is assignment-compatible with the object represented by this Class. This method is the dynamic equivalent of the Java language instanceof operator .