Question

I have the class:

class SomeClass<T extends SomeInterface>{

   private T[] myArray;

   public SomeClass()
   {
       // I want to initialize myArray in here to a default size of 100
       myArray = new T[100];  // this gives an error
   }

}

I know I can fix that by requiring a parameter in the constructor as:

class SomeClass<T extends SomeInterface>{

   private T[] myArray;

   public SomeClass(Class<T> clazz)
   {       
       myArray= (T[]) Array.newInstance(clazz, 100);
   }

}

but it makes no scene having to pass the generic parameter twice.

in other words in order to instantiate an object from the class SomeClass I will have to do something like:

SomeClass<SomeOtherClass> obj = 
      new SomeClass<SomeOtherClass>(SomeOtherClass.class);

I program in c# and Java does not seem to be friendly. I don’t even understand why it is not possible to cast Object[] array to SomeOtherClass[] array. In c# that will be possible…

so my question is how can I avoid having to pass the SomeOtherClass.class parameter in order to be able to construct an array of the generic type in the constructor of the class…

Answer 1

Yes, you would have to pass in the .class like that in order to make this work.

You could avoid all of this and just use an ArrayList<T> instead. When you need it in the form of an array you can use: (T[]) myArrayList.toArray()