The Java Language Specification, Third Edition

4.10.3 Subtyping among Array Types TYPES, VALUES, AND VARIABLES
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• The type Object, if C is an interface type with no direct superinterfaces.
• The raw type C.
The direct supertypes of the type C , where Ti, 1 ≤i≤n, is a
type, are D, where
• D is a direct supertype of C, and theta is the substitution
[F1 := T1, ..., Fn := Tn]. • C where Si contains (§4.5.1.1) Ti for 1 ≤i≤n. The direct supertypes of the type C , where at least one of the Ri, 1 ≤i≤n, is a wildcard type argument, are the direct supertypes of C, where
C is the result of applying capture conversion (§5.1.10) to
C. The direct supertypes of an intersection type (§4.9) T1 & ... & Tn, are Ti, 1 ≤i≤n. The direct supertypes of a type variable (§4.4) are the types listed in its bound.
The direct supertypes of the null type are all reference types other than the
null type itself.
In addition to the above rules, a type variable is a direct supertype of its lower
bound.
4.10.3 Subtyping among Array Types
The following rules define the direct subtype relation among array types:
• If S and T are both reference types, then S[] > 1 T[] iff S > 1 T.
• Object > 1 Object[]
DRAFT
• Cloneable > 1 Object[]
• java.io.Serializable >1 Object[]
• If p is a primitive type, then:
◆ Object >1 p[]
◆ Cloneable >1 p[]
◆ java.io.Serializable >1 p[]