Change the specific word's color in the row JTable

Question

As @mKorbel stated you can use HTML tags in Swing: How to Use HTML in Swing Components

Also you'll need a custom cell renderer: Using Custom Renderers

Example

This is just an example of implementation (it's not exactly what you need) but you can manage to make it more accurate:

table.setDefaultRenderer(Object.class, new DefaultTableCellRenderer(){

    @Override
    public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) {

        super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);

        String str = value.toString();
        String regex = ".*?user=\".*?\".*?";
        Matcher matcher = Pattern.compile(regex).matcher(str);
        if(matcher.matches()){
            regex = "user=\".*?\"";
            matcher = Pattern.compile(regex).matcher(str);
            while(matcher.find()){
                String aux = matcher.group();
                str = str.replace(aux, "<b>" + aux + "</b>");
            }
            str = "<html>" + str + "</html>";

            setText(str);
        }                
        return this;                
    }            
});

This renderer looks for user="whateverHere" pattern in the string. If it matches then replaces all instances of this sub-string with the same sub-string sorrounded by <b></b> tags. Finally sorrounds the whole text with <html></html> tags.

More info about regex in this Q&A: Using Java to find substring of a bigger string using Regular Expression

As DefaultTableCellRenderer extends from JLabel (yes, a Swing component!) HTML tags will do the trick.

Screenshot

enter image description here