CODE EXAMPLE FOR JAVA

Copying value from one input field to another input field using checkbox

function copyTextValue(bf) {
  var text1 = bf.checked ? document.getElementById("Name1").value : '';
  document.getElementById("Name2").value = text1;
  document.getElementById("Name3").value = text1;
}

<input type="checkbox" name="check1" onchange="copyTextValue(this);" />
<input id="Name1"><input id="Name2"><input id="Name3">