Creation date: 14 March, 2011

Implicit typecasting

Java makes some impicit typecasting when we assign one primitive type to another broader promitive type. But we can't do it with wrappers. Because all numeric wrappers are extend Numeric, but not each other. You can write

byte b = 5;
int i = b;

But you can not write

Long l = new Integer(6);

Now let's look at arrays

class A{}
class B extends A{}

public class Test {
  int[] intArr;
  byte[] byteArr = {2, 5, 10};
  A[] aArr;
  B[] bArr = new B[5];

  public static void main(String[] args) {
    Test test = new Test();
    test.intArr = test.byteArr; //will not compile
    test.aArr = test.bArr; //correct and will compile
  }
}

Although Java casts byte to int implicitly, it can't cast byte[] to int[] neither implicitly nor explicitly. But in case of inherited object it compiles fine.

Author: Jafar N.Aliyev (Jsoft)

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