Build me a Web App - Volunteer App (Java, javacript, HTML, CSS) - $50 fixed Rate

I need Real-time App using Java, where people can find volunteers who can help them. The App must include real-time map location of both users. The people can ask for help, and the volunteer can check the help needed near their location and can initiate chat with the other person and discuss about the kind of help needed.
There will be two side, login as a volunteer or need help.