Copying Generic Arrays in Java
a day ago
- Copying generic arrays in Java is problematic due to type erasure, as generic array creation is not allowed directly.
- Using clone() on an existing array works to preserve order and create a new instance, but creating a new generic array via 'new T[]' is a compile-time error.
- Casting 'new Object[]' to a generic array type can lead to a ClassCastException at runtime with no traceback, pointing to the calling method instead of the faulty line.
- The Java compiler translates 'new T[]' into java.lang.reflect.Array.newInstance, which requires the actual class object; type parameters are erased and unavailable.
- A workaround is to obtain the class from an existing instance (e.g., via getClass()) or to return null if the array is empty, avoiding the need for reflection.