You forgot the .class: if (value.getClass() == Integer.class) { System.out.println(“This is an Integer”); } else if (value.getClass() == String.class) { System.out.println(“This is a String”); } else if (value.getClass() == Float.class) { System.out.println(“This is a Float”); } Note that this kind of code is usually the sign of a poor OO design. Also note that comparing the … Read more
How do I create static class variables or methods in Python? 2 25
This question already has answers here: What does ‘super’ do in Python? – difference between super().__init__() and explicit superclass __init__() (11 answers) Closed 6 years ago. Why is super() used? Is there a difference between using Base.__init__ and super().__init__? class Base(object): def __init__(self): print “Base created” class ChildA(Base): def __init__(self): Base.__init__(self) class ChildB(Base): def __init__(self): … Read more
If a constructor does not explicitly invoke a superclass constructor, the Java compiler automatically inserts a call to the no-argument constructor of the superclass. If the super class does not have a no-argument constructor, you will get a compile-time error. Object does have such a constructor, so if Object is the only superclass, there is … Read more
int is a primitive type. Variables of type int store the actual binary value for the integer you want to represent. int.parseInt(“1”) doesn’t make sense because int is not a class and therefore doesn’t have any methods. Integer is a class, no different from any other in the Java language. Variables of type Integer store references to Integer objects, just as with any other reference (object) type. Integer.parseInt(“1”) is a call to the … Read more
Java Class File Editor
I am having a problem with calling a method that is in a different class. This main method is in a class on its own called lab14, and the heapSort() method is in a different class called HeapSort. Both of these classes are in the default package. I am getting the error “The method heapSort(Vector) … Read more
Finally, I modified the sort function in this manner to get sorted data. Collections.sort(ls, new Comparator() { public int compare(Object o1, Object o2) { String sa = (String)o1; String sb = (String)o2; int v = sa.compareTo(sb); return v; // it can also return 0, and 1 } } );
Import a custom class in Java
You can’t create arrays with a generic component type. Create an array of an explicit type, like Object[], instead. You can then cast this to PCB[] if you want, but I don’t recommend it in most cases. PCB[] res = (PCB[]) new Object[list.size()]; /* Not type-safe. */ If you want type safety, use a collection like java.util.List<PCB> instead of an … Read more
