Chapter 2 Using the Signature Test Tool 11
Signature File Merge Rules
The -Files argument of the SignatureTest command accepts values to specify
one or more signaturefiles that are combined to represent an API configuration that
is used as input for testing. This resulting API-set can also be combined into a single
signature file for testing purposes.
By default the API combination is assumed to be constructed accordingto the JSR 68
rules. This can be overridden during a SigTesttool test run by specifying the
-NoMerge option to run the signature test. The -NoMerge option forcesSigTest tool
to use the first class description it encounters if more than one class with the same
name is found in the set of signature files specifiedby the -Files argument. In this
case it uses the class from the left-most signature filethat is specified with -Files.

JSR 68-Based Merge

The Java ME platform architecture specified by JSR 682allows for the inclusion of
several Java platform APIs in one conforming Java platform runtime environment.
The condition for combining these APIs is that any application written for the
resulting runtime environment must execute successfully on the combination.
If such a combination exists, it is defined on the basis of the combined sets of APIs
with semantics, and the semantics must be compatible with those of all the included
components.
The only means of verifying the semantics of the combination is to run the
applicable test suite for each API. However,it is possible to automate the creation of
a combined set of API signatures, and it is also possible to detect when a combined
set cannot be built.
The Merge command functionality combines (merges) several input signature files
into one resulting signature file,as follows: If A, B, and C are signaturefiles, then A
+ B yields signature file C, and each of the three signaturefiles represent the
corresponding classes of their respective APIs. The Merge process constructs the
resulting API C out of the two input APIs A and B.

Merge Command Operative Principles

The Merge command operates according to thefollowing principles, whereA and B
are input APIs that are combined into the resulting API C:
2.http://jcp.org/en/jsr/detail?id=68