Parsing a java expression

Question

Write a program in Java that can parse a mathematical expression
String, calculate the expression, and produce a numeric result.
For example, given the string: "2.5+3*4+6/12-7" produce the result 8.0
Requirements: Parser
* expression can contain Integers or floating-point numbers
* expression can contain Operators for addition, subtraction, division
and multiplication
* parser should throw an Exception when the expression is invalid
Requirements: Solution
* Implement the solution in Java
* Compile and test the solution
* The solution should demonstrate good modularity, be self-contained,
reusable and extensible.
* The solution should be clearly written, easy to read, documented, and
production-quality.
Requirements: quality
* This is a timed exercise and should be completed quickly, however you
should take sufficient time to produce a quality result
* A quality solution is simple, concise, complete, well documented,
readable, adaptable, reusable, testable and robust.

Answer 1

If your assignment was to:
1) figure out how to create a login on the forums
2) cut-and-paste verbiage given to you by someone
3) create a topic in the forums with the above
then you get an 'A'. Congratulations!