You dont have to give any quotes!
Just {%personalMessage%} is enough.
More importantly you need to pass the data object which contains the data that this placeholder should replace. Are you passing that to the Java Action or the MF you are using?
FYI 1 such java action is Send Email with Template which takes in the DataObject which has the attributes that the tokens should replace, EmailAccount and EmailTemplate. I just tested and it works well.