irb(main):005:0> checkbox = Java::javax::swing::JCheckBox.new
=> #<Java::JavaxSwing::JCheckBox:0xf6e9d @java_object=javax.swing.JCheckBox[,0,0,0x0,invalid,alignmentX=0.0,alignmentY=0.5,border=apple.laf.CUIAquaButtonBorder$Named@272332,flags=288,maximumSize=,minimumSize=,preferredSize=,defaultIcon=,disabledIcon=,disabledSelectedIcon=,margin=javax.swing.plaf.InsetsUIResource[top=1,left=1,bottom=0,right=1],paintBorder=false,paintFocus=true,pressedIcon=,rolloverEnabled=false,rolloverIcon=,rolloverSelectedIcon=,selectedIcon=,text=]>
irb(main):006:0> checkbox.selected = true
=> true
irb(main):007:0> checkbox.selected
=> true
irb(main):008:0> checkbox.selected?
=> true
irb(main):009:0> checkbox.selected = false
=> false
irb(main):010:0> checkbox.selected
=> false
irb(main):011:0> checkbox.selected?
=> false