The UG says in A.2.1 (7) (see screenshot attached):
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Use the SignatureTest command to compare the V2.0 API signature with the V1.0 signature file you created in Step 5.
% java com.sun.tdk.signaturetest.Setup -classpath V2.0:$JAVA_HOME/jre/lib/rt.jar -static -package example -fileName test.sig -out report.txt
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I suppose it should be:
% java com.sun.tdk.signaturetest.SignatureTest -classpath V2.0:$JAVA_HOME/jre/lib/rt.jar -static -package example -fileName test.sig -out report.txt