Unless I'm misunderstanding your intention (change value of bInA from C), your recent edit seems to work fine. Here's my java version of your pseudocode.
class A
{
B bInA;
C cInA;
public void foo(int someValue)
{
cInA = new C();
bInA = new B();
cInA.foo(bInA, someValue);
System.out.println(bInA.value);
}
public static void main(String args[])
{
A myA = new A();
myA.foo(123);
// myA.bInA.value should be equal to xyz
}
}
class B { int value; }
class C
{
public void foo(B bInA, int someValue)
{
bInA.value = someValue;
}
}
Output
123