How to document my method in Java like Java docs?

How do you explain what the Params Stands for?

Use @param tag:

/**
 * @param paramName Explanation of the param
 */
public void foo(String paramName);

How do you create a new line, or make a word bold or italic?

Use standard HTML, i.e. <p></p>, <br/>, <strong> and <em> (or less semantic <b> and <i>)

In most major IDEs, such as IntelliJ's IDEA, Apache Netbeans or Eclipse; you can type

/**

and press enter and it will generate the Javadoc for your method, including parameters, return values, etc. You just need to put in the descriptions.

The same applies for class declarations (the Javadoc comment always relates to the following element)

For instance

/**
 * create_instance
 * @param array of attributes for instance containing web, db, arrival_rate, response_time for instance 
 * respectively.
 * @return Instance object
 */