How to Check If a String is Not Equal to Another String in Java?

In Java, checking if a string is not equal to another string means comparing two string objects and determining whether they contain the same characters or not. If the two strings are not equal, it means that at least one character in one string is different from the corresponding character in the other string. It is beneficial for various purposes such as input validation, data processing, and error handling.

This guide will explain different methods to compute if a string is not equal to another string in Java.

Using the “!=” Operator
Using the equals() Method
Using the compareTo() Method
Using the compareToIgnoreCase() Method
Using the !equals() Method

Using the “!=” Operator

The “!=” operator is utilized to compare the values of two objects. In Java, strings are objects, and the “!=” operator can be utilized to compute if two strings are not equal. Here is an example:

class HelloWorld {
public static void main(String[] args) {
String str1 = "Hello";
String str2 = "World";
if (str1 != str2) {
System.out.println("The two strings are not equal");
}

}
}

Output

The result of the above code demonstrates that two strings “Hello” and “World” are not equal in the terminal.

Using the equals() Method

This method is utilized to compute the values of two objects. The String class overrides the equals() for computing the values of two strings. Here is an example:

String str1 = "Hello";
String str2 = "World";
if (!str1.equals(str2)) {
System.out.println("The two strings are not equal");
}

Output

The outcome of the above code confirms that the two strings “Hello” and “World” are not equal.

Using the compareTo() Method

The compareTo() method is utilized to compare the lexicographical order of two strings. When these strings are not equal, it returns a value other than zero. Here is an example:

class HelloWorld {
public static void main(String[] args) {
String str1 = "Hello";
String str2 = "World";
if (str1.compareTo(str2) != 0) {
System.out.println("The two strings are not equal");
}
}}

Output

The output shows that two strings are not equal.

Using the compareToIgnoreCase() Method

The compareToIgnoreCase() method is like the compareTo() method, but it ignores the case of the strings. Here is a code:

class HelloWorld {
public static void main(String[] args) {
String str1 = "Hello";
String str2 = "WORLD";
if (str1.compareToIgnoreCase(str2) != 0) {
System.out.println("The two strings are not equal");
}}
}

Output

The output shows that strings are not equal.

Using the !equals() Method

The !equals() method is utilized to compute whether two strings are equal or not. Here is an example:

class HelloWorld {
public static void main(String[] args) {
String str1 = "Hello";
String str2 = "World";
if (!str1.equals(str2)) {
System.out.println("The two strings are not equal");
}}
}

Output

The output confirms that strings are not equal.

Conclusion

In Java, check if a string is not equal to another string, utilize the “!=” operator, the equals() method, the compareTo() method, or the !equals() method. All these methods are utilized to compute whether one string is equal or not to another string in Java. The selection of the method is based on the specific needs of the program and the desired level of string comparison.

How to Check If a String is Not Equal to Another String in Java?

Using the “!=” Operator

Using the equals() Method

Using the compareTo() Method

Using the compareToIgnoreCase() Method

Using the !equals() Method

Conclusion

About the author

Syed Minhal Abbas