equals():Compare two string value for equality

boolean equals(Object anObject): Compares this string to the specified object.
boolean equalsIgnoreCase(String anotherString): Compares this String to another String, ignoring case considerations.


public class MainClass {
  public static void main(String args[]) {
  String s1 = "Hello";
  String s2 = "Hello";
  String s3 = "Goodbye";
  String s4 = "HELLO";
  System.out.println(s1 + " equals " + s2 + " -> " + s1.equals(s2));
  System.out.println(s1 + " equals " + s3 + " -> " + s1.equals(s3));
  System.out.println(s1 + " equals " + s4 + " -> " + s1.equals(s4));
  }
}

/*
 * Output:


  Hello equals Hello -> true
  Hello equals Goodbye -> false
  Hello equals HELLO -> false
   
 * */

The following code checks the length of a string, then gets the fourth char out of the string object and compares these two string objects.


public class Main {
  public static void main(String args[]) {
    String strOb1 = "java2s.com";
    String strOb2 = "java2s.com";
    String strOb3 = strOb1;

    System.out.println("Length of strOb1: " + strOb1.length());
    System.out.println("Char at index 3 in strOb1: " + strOb1.charAt(3));

    if (strOb1.equals(strOb2))
      System.out.println("strOb1 == strOb2");
    else
      System.out.println("strOb1 != strOb2");

    if (strOb1.equals(strOb3))
      System.out.println("strOb1 == strOb3");
    else
      System.out.println("strOb1 != strOb3");
  }
}

This program generates the following output:


Length of strOb1: 10
Char at index 3 in strOb1: a
strOb1 == strOb2
strOb1 == strOb3

The comparison is case-sensitive.


public class Main {
  public static void main(String args[]) {
    String s1 = "Hello";
    String s2 = "Hello";
    String s3 = "Good-bye";
    String s4 = "HELLO";
    System.out.println(s1 + " equals " + s2 + " -> " +

    s1.equals(s2));
    System.out.println(s1 + " equals " + s3 + " -> " + s1.equals(s3));
    System.out.println(s1 + " equals " + s4 + " -> " + s1.equals(s4));
    System.out.println(s1 + " equalsIgnoreCase " + s4 + " -> " + s1.equalsIgnoreCase(s4));
  }
}

The output:



Hello equals Hello -> true
Hello equals Good-bye -> false
Hello equals HELLO -> false
Hello equalsIgnoreCase HELLO -> true

To compare igoring case, call equalsIgnoreCase( ). It has this general form:


boolean equalsIgnoreCase(String str)

str is the String object being compared with the invoking String object. Here is an example that demonstrates equals( ) and equalsIgnoreCase( ):


public class Main {
  public static void main(String args[]) {
    String s1 = "Hello";
    String s2 = "Hello";
    String s3 = "Good-bye";
    String s4 = "HELLO";
    System.out.println(s1 + " equals " + s2 + " -> " +

    s1.equals(s2));
    System.out.println(s1 + " equals " + s3 + " -> " + s1.equals(s3));
    System.out.println(s1 + " equals " + s4 + " -> " + s1.equals(s4));
    System.out.println(s1 + " equalsIgnoreCase " + s4 + " -> " + s1.equalsIgnoreCase(s4));
  }
}

The output from the program is shown here:


Hello equals Hello -> true
Hello equals Good-bye -> false
Hello equals HELLO -> false
Hello equalsIgnoreCase HELLO -> true