String compareTo vs equals in Java

Introduction

In Java, String is one of the most frequently used classes and it provides a number of methods to perform various operations on strings. Two of the most commonly used methods are the compareTo() and equals() methods. These methods are used to compare two strings for equality or order.

String equals() Method

The equals() method is used to compare two strings for equality. As the name suggests, it compares the actual contents of two strings to check if they are equal. The return value of the equals() method is a boolean value (true or false) that indicates whether the strings are equal or not.

Example

String s1 = "Hello";
String s2 = "Hello";
boolean isEqual = s1.equals(s2);
System.out.println(isEqual); // Output: true

String compareTo() Method

The compareTo() method is used to compare two strings lexicographically. It compares the two strings based on their Unicode values. The return value of the compareTo() method is an integer value that indicates the relationship between the two strings.

Example

String s1 = "apple";
String s2 = "banana";
int result = s1.compareTo(s2);
System.out.println(result); // Output: -1

Comparison Table

|equals()|compareTo()| |--------|-----------| |Used to check for equality|Used to compare two strings lexicographically| |Compares the contents of the strings|Compares the Unicode values of the strings| |Returns a boolean (true or false) value|Returns an integer value that indicates the relationship between the two strings| |Syntax: s1.equals(s2)|Syntax: s1.compareTo(s2)|

Conclusion

Both equals() and compareTo() methods are important for string comparison in Java. While the equals() method checks if two strings are equal, the compareTo() method compares the strings lexicographically. It's important to choose the right method depending on the scenario.