Can anyone help me in implementing simple java program for evaluation of mathematical expression?

Question

for example if we take 2-5*4/2 as a input string, we should get a result of above expression at output.

Answer 1

i think you can find an answer here :

https://stackoverflow.com/questions/935175/convert-string-to-code

Answer 2

goto Google
look up ruslan spivak let us build a simple interpreter in Python. yes, Python.
read through the ten or so posts
when you understand enough of it, use it as a specification to write an interpreter using Java

best wishes