java – How to replace the word independently of the case

I can get a variant of the word "the" or "THE" or some other mixture of upper and lower case, but how can I replace everything without distinction of case ?. What I have is:
Public class StringPlay {
// find all the occurrences of the word the in my essay
public StringPlay (String s)
{}

public String ridOfThes (String Test)
{
String s = "The weakness lies in the legs of the jaws, in the teeth of the days and in the rent of the lake.";
String change = s.replaceAll ("the", "z");
give back change;
}
public static void main (String[] args) {
StringPlay stringPlay = new StringPlay ("The weakness lies in the legs of the jaws, in the tooth of the days and in the rent of the lake.");
System.out.println (stringPlay.ridOfThes ("The weakness lies in the legs of the jaws, in the teeth of the days and in the rent of the lake."));
}

}

The exit here is:
"The weakness lies in z legs of z jaws, in z teeth z days and z renting of z lake."