Java array of object which has generic

Question

I have the following structure:

public class SomeObject<T> {

    int key;
    T value;
    ...
}

And in another class:

public class TestSomeObject<T> {

    SomeObject<T>[] data;

    TestSomeObject() {
         this.data =  (SomeObject<T>[]) new Object[capacity];
    }
}

Of course, that line in the constructor utterly fails with the Exception:

[Ljava.lang.Object; cannot be cast to [SomeObject;

Are there any workarounds for this? Or is there any way I could restructure it to make it work?

What do you wish this to do : `this.data = (SomeObject[]) new Object[capacity];`? — TJ-, Aug 07 '15 at 09:13
http://stackoverflow.com/questions/2434041/instantiating-generics-type-in-java — KarimS, Aug 07 '15 at 09:15

score 3 · Accepted Answer · answered Aug 07 '15 at 09:16

3

Use

@SuppressWarnings("unchecked")
TestSomeObject() {
     this.data =  new SomeObject[capacity];
}

answered Aug 07 '15 at 09:16

wero

32,544
3
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score 0 · Answer 2 · answered Aug 07 '15 at 09:26

You cant't cast an new Object() to SomeObject.

Maybe you want something like this?

public class TestSomeObject<T> {

  SomeObject<T>[] data;

  TestSomeObject() {
       this.data =  new SomeObject[] {new SomeObject<T>()};
  }

  public static void main(String... args) {
    new TestSomeObject<String>();
  }

}

score 0 · Answer 3 · answered Aug 07 '15 at 09:44

0

If Object in "new Object[capacity];" is java.lang.Object, it's normal. You can't cast a new Object into anything. You have to do:

this.data = new SomeObject<T>[capacity];

answered Aug 07 '15 at 09:44

Asoub

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Java array of object which has generic

3 Answers3