Object life cycle in java and memory management?

Object life cycle in java and memory management?

for this statement in a program how many objects will be created in a heap
memory and in a string constant pool.
need clarity in object creation, many sources i referred not elaborating
it. i am confused when the object gets destroyed .
String a="MAM"+"BCD"+"EFG"+"GFE";
How many objects will be created?