getA() would do pointer dereferencing,
so I would suggest doing
A a = getA();
a.method();
a.method();
because it's generaly easier to maintain, and the
code block only dereference once, then kept the
reference for later use in 'a'
to be exact, I would use one over the other depending on the code block.
i.e:
// no need to grab A, coz it's pointless
public
String method aaa_simple()
{
this.B.getA().getAddress();
}
// grab reference to A, makes life easier
public String method aaa_long_andComplex()
{
A a = this.B.getA();
String somethingGenerated;
// do some operation with a.getAddress()
// some more operation with a.getWhatever()
// some more operation with a.getWhatHaveYous()
return somethingGenerated;
}