Sun Microsystems 2 Mutual Source Compatibility Check, Class and Class Member Attributes Checked

Mutual Source Compatibility Check

While binary compatibility is important, it cannot guarantee that an application in binary form as a set of class files can be recompiled without error.

The signature test source compatibility check mode verifies that any application that compiles without error with a compatible API, compiles without error with all other source compatible APIs.

Mutual source compatibility is a stricter check than the mutual binary compatibility and SigTest tool performs it by default.

Class and Class Member Attributes Checked

A Java platform API consists of classes, and interfaces, and their member fields, methods, and constructors, and documented annotations. In turn, all of these API items can have various attributes such as names, modifiers, a list of parameters, a list of interfaces, exceptions, nested classes, and so forth. A signature test checks that certain members and attributes belonging to the API under test are the same as those defined by the API to which it is being compared. The signature test checks public and protected API items only and ignores private and package-access items.

The tool checks the following attributes when comparing items in the API implementation under test:

■Classes and interfaces, including nested classes and interfaces:

■Set of modifiers except strictfp

■Name of the superclass

■Names of all superinterfaces, direct plus indirect, where order is insignificant

■Constructors:

■Set of modifiers

■List of argument types

■In source compatibility mode only, the normalized list of thrown exceptions where order is insignificant

Normalizing the throw lists involves removing all superfluous exception classes. An exception class is superfluous if it is a subclass of either the java.lang.RuntimeException class, the java.lang.Error class, or another class from the same list.

■Methods:

■The set of modifiers, except strictfp, synchronized, and native

■The return type

■The list of argument types

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