Java - utilisation correcte des arrayBaseOffset et arrayIndexScale - Stack Overflow

I have defined a simple array and I want to use Unsafe.arrayBaseOffset and Unsafe.arrayIndexScale with the following snippet.

import sun.misc.Unsafe;
public class Arr
{
  public static void main(String[] args)
  {
    int [] a = new int[3];
    a[0] = 10; a[1] = 20; a[2] = 30;
    int baseOffset = Unsafe.arrayBaseOffset(a.getClass());
    int indexScale = Unsafe.arrayIndexScale(a.getClass());
  }
} 

However I get these errors

Arr.java:11: non-static method arrayBaseOffset(java.lang.Class) cannot be referenced from a static context
    int baseOffset = Unsafe.arrayBaseOffset(a.getClass());
                           ^

Arr.java:12: non-static method arrayIndexScale(java.lang.Class) cannot be referenced from a static context
    int indexScale = Unsafe.arrayIndexScale(a.getClass());
                           ^

The arrayBaseOffset and arrayIndexScale methods are not static, so you cannot call them the way you are. You need to do it like this:

    Unsafe u = Unsafe.getUnsafe();
    int baseOffset = u.arrayBaseOffset(a.getClass());
    int indexScale = u.arrayIndexScale(a.getClass());

I have defined a simple array and I want to use Unsafe.arrayBaseOffset and Unsafe.arrayIndexScale with the following snippet.

import sun.misc.Unsafe;
public class Arr
{
  public static void main(String[] args)
  {
    int [] a = new int[3];
    a[0] = 10; a[1] = 20; a[2] = 30;
    int baseOffset = Unsafe.arrayBaseOffset(a.getClass());
    int indexScale = Unsafe.arrayIndexScale(a.getClass());
  }
} 

However I get these errors

Arr.java:11: non-static method arrayBaseOffset(java.lang.Class) cannot be referenced from a static context
    int baseOffset = Unsafe.arrayBaseOffset(a.getClass());
                           ^

Arr.java:12: non-static method arrayIndexScale(java.lang.Class) cannot be referenced from a static context
    int indexScale = Unsafe.arrayIndexScale(a.getClass());
                           ^

The arrayBaseOffset and arrayIndexScale methods are not static, so you cannot call them the way you are. You need to do it like this:

    Unsafe u = Unsafe.getUnsafe();
    int baseOffset = u.arrayBaseOffset(a.getClass());
    int indexScale = u.arrayIndexScale(a.getClass());

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