java - Is there No Point to use instanceof with primitive types array? -

this somehow same asking: is there subclass / superclass primitive types?

(because ((object) (new string[6])) instanceof object[] true, string extends object.)

for instance, of int[], only ((object) (new int[3])) instanceof int[] true, among in java?

if so,

((object) (new int[3])) instanceof int[] 

is identical to

((object) (new int[3])).getclass() == int[].class 

and prefer latter one, should faster, doesn't have check every type/class inheritances.

it difficult understand asking, think asking whether using getclass() better using instanceof array types.

from perspective of readability, instanceof better:

   object obj = new int[3];     if (obj instanceof int[]) {        int[] array = (int[]) obj;    }     if (foo.getclass() == int[].class) {        int[] array = (int[]) obj;    } 

clearly, first form more readable.

from performance perspective, cannot see why 2 versions could not identical. in instanceof case, int[] type has no subtypes, , therefore can compiled equivalent or potentially faster than getclass() version.

the way sure faster write decent microbenchmark , run on platforms interested in. , note liable different performance results different versions of java

however, suspect performance difference small make difference application. unless already have concrete profiling results point bottleneck ... wasting time.

---

this somehow same asking: there subclass / superclass primitive types?

no. not equivalent asking @ all. java array types not primitive types. reference types.

it related question of whether there subtype relationship between array types. or more accurate, boils down whether can cast 1 array type different array type.

and answer depends on base type; see jls 5.5.1. reference type casting. if base types (different) primitive types, answer no. if base types reference types, if can cast 1 base type (bc1) other (bc2) cast involving array types (bc1[] bc2[]) legal.

so means instanceof , getclass() tests give same answer array-of-primitive types, not array types.

---

in fact, arguably mistake in original java language design allow any casting between different array types. leads anomalies such this:

    object[] = new string[1];     a[0] = new object();  // throws arraystoreexception !!!