Unable to customize the button for my plugin

Hi Team,

I am unable to apply style (color) fully for my Button, when I try to do that it ends up coloring only the border.

Note: this button will be used in a plugin which will be deployed

Expected:

My Output:

My Implementation:
JButton test = new JButton("Test");
test.setPreferredSize(new Dimension(150,30));
test.setBackground(new Color(12,159,167));
jpanel.add(test);