String contentEquals() method - Syntax and Examples

Java String contentEquals() method - Syntax and Examples

This reference explains String contentEquals() method - Syntax and Examples through its syntax, examples and boundaries. Use the linked course lessons when the surrounding Java concepts are unfamiliar.

The contentEquals() method in Java provides a way to compare the content of two strings or character sequences. Unlike the standard equals() method, which considers Unicode values and normalization forms, contentEquals() performs a simpler comparison based on characters.

    public boolean contentEquals(CharSequence cs)
    public boolean contentEquals(StringBuffer sb)
    

This method returns true if the content of the two sequences are equal; otherwise, it returns false.

Let's start by looking at a straightforward example where we compare two strings using contentEquals(). We'll also compare it to the standard equals() method to highlight the differences.

    import java.util.*;\n
public class ContentEqualsExample {\n    public static void main(String[] args) {\n        String str1 = "Hello";\n        String str2 = "Hello";\n        String str3 = "hello";\n
        System.out.println("str1.contentEquals(str2): " + str1.contentEquals(str2));\n        System.out.println("str1.contentEquals(str3): " + str1.contentEquals(str3));\n        System.out.println("str1.equals(str2): " + str1.equals(str2));\n        System.out.println("str1.equals(str3): " + str1.equals(str3));\n    }\n}
    
    

str1.contentEquals(str2): true
str1.contentEquals(str3): false
str1.equals(str2): true
str1.equals(str3): false

In this example, both contentEquals() and equals() return true when comparing str1 and str2 because they contain the same characters in the same order. However, when comparing str1 (which is "Hello") with str3 (which is "hello"), both methods correctly identify them as different due to case sensitivity.

Now, let's see how contentEquals() behaves when comparing a String with a StringBuffer. They are distinct classes, but their content can still be compared.

    import java.util.*;\n
public class StringBufferContentEqualsExample {\n    public static void main(String[] args) {\n        String str = "Java";\n        StringBuffer sb = new StringBuffer("Java");\n
        System.out.println("str.contentEquals(sb): " + str.contentEquals(sb));\n    }\n}
    
    

str.contentEquals(sb): true

Here, contentEquals() returns true because the string "Java" and the StringBuffer containing "Java" have identical content.

You can also compare using any object that implements CharSequence. This provides flexibility when dealing with different character sequence representations.

        import java.util.*;

public class CharSequenceContentEqualsExample {
    public static void main(String[] args) {\n        String str = "Test";\n        CharSequence cs = "Test"; // String implements CharSequence

        System.out.println("str.contentEquals(cs): " + str.contentEquals(cs));
    }
}
    

str.contentEquals(cs): true

The main difference between contentEquals() and equals() lies in their handling of Unicode normalization forms. If you need a simple, character-by-character comparison without considering normalization issues, contentEquals() is generally faster and more appropriate.

Use contentEquals() when:

• You want a quick and straightforward content comparison.
• Unicode normalization forms are not relevant to your comparison logic.

Check the example’s types, inputs and documented behavior before copying it into an application. Some APIs require external libraries, files or platform services; consult their setup notes.

Related explanations: Java Data Types - Primitive and Non-Primitive, Java Class - Blueprint of Objects, Exceptions in Java Introduction.

Supporting documentation: Official Java learning guide.