Notice that Product.fileset.a was only updated in PTF 1 and this update would not be installed if you only installed PTF 2.
How do I know which filesets I have installed?
If you have installed all of the PTFs, you know that you have all of the latest updates. Another way is to check the fileset level. Although PTFs (a PTF being a set of fileset updates) are not cumulative, fileset updates are cumulative. For example, if you have Product.fileset.b at 1.3.1.0 and you have not installed Product.fileset.b 1.3.1.1 or 1.3.1.2, then you only need to install Product.fileset.b 1.3.1.2. This is because all of the changes in Product.fileset.b 1.3.1.1 would also be in or superseded by the changes in Product.fileset.b 1.3.1.2. So, for SDK 1.3.1, if you run the AIX command
lslpp -L | grep Java131
to find out what level you have installed on your machine, and compare this with the latest fileset update levels
From IY92309:
Java131.rte.bin.1.3.1.21
Java131.rte.lib.1.3.1.21
Java131.ext.plugin.1.3.1.20
Java131.adt.debug.1.3.1.18
From IY65310:
Java131.adt.includes.1.3.1.6
From IY65310:
Java131.ext.jaas.1.3.1.6
From IY49074:
Java131.ext.commapi.1.3.1.2
Java131.samples.demos.1.3.1.3
From IY30887:
Java131.ext.xml4j.1.3.1.1
Java131.ext.java3d.1.3.1.1
then you can find out if you have all of the latest updates installed (if you do not, the above list tells you from which APAR(s) you can get the fileset updates you need.)
Note: If you did not install some of the GA filesets (you may have decided that you do not need some or all of Java131.adt or Java131.ext filesets), then you will not need any updates to those filesets.