Phil Maqui wrote:i tried finding stuff on the net on how to do this, but all in vain, . . .
Just as well you didn’ find anything. As you will see here,
We're all here to learn, so when responding to others, please focus on helping them discover their own solutions, instead of simply providing answers.
. . . you are better off working it out for yrruself.
To work it out for yourself, you need some very high-technology with curvilinear frictional recolorisation, two-dimensional illuminative inspection capabilities, and polymeric deletion. That means: pencil, paper and eraser The last-named is probably the most important.
Write down what you think you want to do to reverse the String. Hint: go through the String class, and you will find methods which can supply you with the information you need from the String. Once you have it written down, and got it into words of one syllable, then you have it in a form the computer can understand, and which you can convert to code.