Linked Questions

Given String className = "com.example.MyClass"; How would I be able to check if this class implements a specific interface? I've tried Class myClass = Class.forName(className); if (myClass ...

I'm a newbie to Java and want to write a method checking if this object is of a sub class of given class <p_SuperClassName>. Eclipse denies compilation of the following code giving the message ...

I am working on an application and one design approach involves extremely heavy use of the instanceof operator. While I know that OO design generally tries to avoid using instanceof, that is a ...

What is the 'instanceof' operator used for? I learned that Java has the instanceof operator. Can you elaborate where it is used and what are its advantages?

Let clazz be some Class and obj be some Object. Is clazz.isAssignableFrom(obj.getClass()) always the same as clazz.isInstance(obj) ? If not, what are the differences?

I have a Class object. I want to determine if the type that the Class object represents implements a specific interface. I was wondering how this could be achieved? I have the following code. ...

If I am creating a java class to be generic, such as: public class Foo<T> How can one determine internally to that class, what 'T' ended up being? public ???? Bar() { //if its type 1 ...

In Java, is it possible to attempt a cast and get back null if the cast fails?

I would like my BallUserInterfaceFactory to return an instance of a user interface that has the proper generic type. I am stuck in the example below getting the error: Bound mismatch: The generic ...

I am just curious to ask this, maybe it is quite meaningless. When we are using instanceof in java, like: if (a instanceof Parent){ //"Parent" here is a parent class of "a" } why we can't use like ...

I want to dynamically tell if an Object in Java is numeric or not. My code is as the following: if(obj.getClass().equals(Number.class)) { attributeTypeStr = "Numeric"; } else { ...

I have a colleague here in my project, who is deeply against the use of instanceof operator, because it "generates a lot of overhead", what is the reason for that? Is it true? Is there another way to ...

How can I say the following: while(input is not an int){ do this } I tried this code but I know it's wrong: int identificationnumber; Scanner sc3 = new Scanner(System.in); identificationnumber = ...

I don't know how to perform type checking on newEntry, I want to make sure that it is of type MyTable (without creating an object of MyTable). public static boolean add(String table, Object newEntry) ...

I have a method for which the return type is object. How do I create a test case for this? How do I mention that the result should be an object? e.g.: public Expression getFilter(String expo) { /...