Revised Picture

In the revised program, the print() method creates a new object and places a reference to it into the parameter st. This is OK as long as the method no longer needs access to the first object.

Note that the second object becomes garbage when the method returns to the caller.

Each color of line in the picture represents a different reference value. The picture shows the print() method changing the value in the formal parameter so that it refers to a second object.

Neither the original object, nor the variable message of the main() method are changed. The print() method can use its formal parameter just like any variable, including changing the value it holds.