Create an instance of a class from a string
Is there a way to create an instance of a class based on the fact I know the name of the class at runtime. Basically I would have the name of the class in a string. 8 Answers 8
instantiation
Creating an instance using the class name and calling constructor
Is there a way to create an instance of a particular class given the class name (dynamic) and pass parameters to its constructor. Something like: Object object = createInstance(“mypackage.MyClass”,”MyAttributeValue”); Where “MyAttributeValue” is an argument to the constructor of MyClass. 10 Answers 10
Why is [] faster than list()?
I recently compared the processing speeds of [] and list() and was surprised to discover that [] runs more than three times faster than list(). I ran the same test with {} and dict() and the results were practically identical: [] and {} both took around 0.128sec / million cycles, while list() and dict() took … Read more
How to create a generic array in Java?
Due to the implementation of Java generics, you can’t have code like this: public class GenSet<E> { private E a[]; public GenSet() { a = new E[INITIAL_ARRAY_LENGTH]; // error: generic array creation } } How can I implement this while maintaining type safety? I saw a solution on the Java forums that goes like this: … Read more
Class ‘Room’ is abstract; cannot be instantiated
Class ‘Room’ is abstract; cannot be instantiated
How to create a generic array in Java?
I have to ask a question in return: is your GenSet “checked” or “unchecked”? What does that mean? Checked: strong typing. GenSet knows explicitly what type of objects it contains (i.e. its constructor was explicitly called with a Class<E> argument, and methods will throw an exception when they are passed arguments that are not of type E. See Collections.checkedCollection.-> in that case, you should … Read more
