What is the difference between replace and replaceAll? JAVA

Question

Hello everyone I want to know what is the difference between replace and replaceAll in java when they do the same things in the ex.

String s1 = "Hello everyone";
String s2 = "My name was Abgar was...";
replaceString1 = s1.replace('e', 'a');
replaceString2 = s2.replace("was", "is");
replaceAllString1 = s1.replaceAll("e", "a");
replaceAllString2 = s2.replaceAll("was", "is");
System.out.println(replaceString1);
//Hallo avarona
System.out.println(replaceString2);
//My name is Abgar is...
System.out.println(replaceAllString1);
//Hallo avarona
System.out.println(replaceAllString2);
//My name is Abgar is...