The following lines create a new ImmutableVector3d instance named vector10 with 100.0, 200.0, and 300.0 for the initial values of x, y, and z. The second lines create a new ImmutableVector3d instance named vector20 with 11.0, 12.0, and 13.0 for the initial values of x, y, and z. Then, the code calls the System.out.println method with vector10 and then with vector20 as an argument. Both calls to the println method will execute the toString method for each ImmutableVector3d instance to display the String representation of the immutable 3D vector. Then, the code calls the add method for vector10 with vector20 as an argument and saves the returned ImmutableVector3d instance in vector30.

The last line calls the println method with vector30 as an argument to print the values of x, y, and z for this instance that has the results of the addition operation between vector10 and vector20. Enter the lines after the code that declares the ImmutableVector3d class...