Java check if Checkbox is checked

Use getState()

boolean checked = c1.getState();
if(c1.getState()) {
  //c1 is checked
} else if (c2.getState()) {
  //
}

OR

Checkbox cb = cg.getSelectedCheckbox();
if(null != cb) {
  //not checked
} else {
  System.out.println(cb.getLabel() + " is checked");
}