Thread: Replace function

Hey guys, Im quite new to Java and I do try to learn a bit and try to solve it by myself and I came across this questions regarding replacement strings. Can you guys help me with that please

So here is the question:-

The global replace function is a string-processing algorithm found in every word processor. Write a method that takes three String arguments: a document, a target string, and a replacement string. The method should replace every occurrence of the target string in the document with the replacement string.

So, basically it needs to find a target string where the user put the sentence in and the user input the word that want to be replace and input what to change the word into.

And here is the code I try and I couldn't figure it out

public class Question1 {
public static void Document(){

}

public static final String targetString(String str){
str.matches(regex);
}

public static void replacementString(char oldString, char newString){
oldString =
}
}