String equalsIgnoreCase() vs JDK 7 Objects.equals(Object, Object)

Question

Do I lose anything by replacing the following:

    public final boolean testEquals(String left, String right) {
        if ((left == null && right != null) || (left != null && right == null)) {
            return false;
        } else if (left == null && right == null) {
            return true;
        } else {
            return left.equalsIgnoreCase(right);
        }
    }

With this from the JDK 7 Objects class:

    public final boolean testEquals(String left, String right) {
        return Objects.equals(left,right);
    }

If I lose the case insensitivity, is replacing it with

Objects.equals(left.toLowerCase(),right.toLowerCase()); 

enough? Does it make sense to?

Answer 1

If you are not only limited to JDK you can use

StringUtils.equalsIgnoreCase(CharSequence str1, CharSequence str2)

from apache-commons lang which is null-safe and will return

 StringUtils.equalsIgnoreCase(null, null)   = true
 StringUtils.equalsIgnoreCase(null, "abc")  = false
 StringUtils.equalsIgnoreCase("abc", null)  = false
 StringUtils.equalsIgnoreCase("abc", "abc") = true
 StringUtils.equalsIgnoreCase("abc", "ABC") = true

Answer 2

The method String.equalsIgnoreCase(String) is "unfortunately" a little more complex. You can look into the code, but it is well explained in the javadoc itself:

Compares this String to another String, ignoring case considerations. Two strings are considered equal ignoring case if they are of the same length and corresponding characters in the two strings are equal ignoring case.

Two characters c1 and c2 are considered the same ignoring case if at least one of the following is true:

• The two characters are the same (as compared by the == operator)
• Applying the method Character.toUpperCase(char) to each character produces the same result
• Applying the method Character.toLowerCase(char) to each character produces the same result